What refrigerant do Koven heat pump RTUs use?

Koven is adopting R-32 (GWP 675) on all new models-this is already under EPA’s Technology Transition limit of 700 GWP, compared with conventional R-410A (GWP 2,088). Using R-32 today future-proofs against ongoing refrigerant regulations.

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RTU with Heat Pump

Q: Does an all-electric heat pump RTU need a backup heating system?

Yes, sized supplemental heat-not full, 100% backup. 'The difference between backup and supplemental heat,' says the University of Illinois EnergySense center, 'is the size of the element-backup supplies 100% of the cooling/heating load in case of failure of the heat pump, and supplemental provides a portion of the load only during the hours that fall below the balance point.' In an all-electric setting, that supplemental means electric resistance- 'all-electric, no gas line' means all-electric equipment, plus supplemental electric resistance, not supplemental gas heat.

Heat Pump RTU: All-Electric Rooftop Units for Commercial Cold-Climate Heating & Cooling

A heat pump RTU (heat pump rooftop unit) is an all-electric, packaged rooftop heating and cooling product that leverages a single reversible refrigerant circuit to heat or cool – basically substituting an all-electric heat pump for a gas-burning furnace in a gas/electric rooftop unit. All-electric rooftop units offer a clear and direct route for buildings facing decarbonization mandates and electrifying their building systems without requiring a costly boiler room upgrade.

There’s one hurdle every mechanical engineer, procurement manager, and facility owner faces: Will a heat pump rooftop unit actually keep a building warm through out the winter? Can it be economically compared to the gas rooftop unit it replaces? This page aims to address these concerns with measured data, including the Koven Air Cold-Climate COP Ladder (down to 30°C/22°F), alongside industry standards, refrigerant regulations, real-world project outcomes, and a tonnage and ROI framework you’ll need to make well-informed decisions for purchasing and specifying.

All-Electric · No Gas Line
EVI Vapor Injection to −30 °C
R-32 Low-GWP Refrigerant
24–40 RT Large-Tonnage HP
AHRI 340/360 Rating Basis
Lifetime Free Technical Service

Specifying a heat pump RTU for a cold-climate or decarbonization project? Calculate your estimated tonnage, building load, and gas-to-electric ROI for your building and climate zone, no strings attached.

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−30 °C

EVI Vapor Injection

24–40 RT

Large-Tonnage Heat Pump

R-32

Low-GWP Refrigerant

Zero Gas

All-Electric Operation

Why Facilities Are Replacing Gas Rooftop Units With Heat Pump RTUs

There are now more reasons than just regulations to ditch the gas rooftop unit; operational and financial concerns are also driving the shift. A trifecta of factors is pushing commercial buildings toward the heat pump rooftop unit, each with a distinct procurement challenge.

In a nutshell: Three primary factors are spurring the transition to heat pump RTUs:

(1) decarbonization and cost savings
according to the U.S. Department of Energy, heat pump RTUs can reduce greenhouse gas emissions and energy expenses by up to half compared to traditional gas-heating rooftop units;

(2) equipment lifespan
the need to replace aging gas/DX rooftop units that have reached the end of their operational life makes the incremental cost of an electric alternative minimal; and

(3) refrigerant transition and building codes
new regulations regarding the phase-out of R-410A refrigerant and updated building-performance standards necessitate equipment updates regardless.

Yet, with only around 15% of commercial buildings in the United States utilizing heat pumps, there’s a significant opportunity for widespread adoption.

The pain: gas-RTU ownership is getting more expensive and less certain

Procurement professionals consistently share in HVAC forums that equipment failure typically involves a specific component like a coil or a heat exchanger, rather than the entire unit, often compounded by challenges in sourcing parts. Facility owners frequently report instances where premium brand packaged heat pumps experience premature evaporator coil failure within two years, or gas pack heat exchangers crack after just one heating season. If the replacement part is unavailable for several months, a purportedly “reliable” brand leaves a building unoccupied with no heating.

These are the exact issues a serious heat pump rooftop unit should effectively address:

Coil and cabinet integrity are primary concerns
leaks in microchannel or V-coils occurring within the 1-5 year range are the most frequently cited reason for buyers discontinuing a brand.

Parts availability and serviceability often take precedence over perceived price
installers value timely access to parts and ease of service over headline cost, recognizing that a building without heat and an unknown restock date represent a substantial cost.

Cold-climate heating certainty is the emotional blocker
the fear that an all-electric unit will “stop working” in a cold snap and blow the power bill on resistance backup.

Total cost versus sticker price decides it
the heat pump cost a little more up front, and the question is whether energy savings and incentives pay it back inside the 1-3 year window buyers expect.

The rest of this page takes those four pains in order – cold-climate performance, all-electric vs. hybrid design, proven results, and cost – and answers each with data rather than adjectives. Building owners weighing a full portfolio should also review the DOE’s Heat Pump RTU Considerations guidance and Koven Air’s commercial rooftop unit range.

The honest trade-off Koven Air engineers for is durability over a spec-sheet average – because every rooftop heat pump is built in-house on our own precision production lines, a replacement part maps to a build record instead of a months-long back-order. Proven in the field across commercial retrofit application from 5 ton branch offices to 40 ton industrial halls, it answers the coil-and-parts failure that retires legacy units early.

Sources: DOE / ACHR News “Advances in Heat Pump Rooftop Units for Cold Climates” (Aug 2024); HVAC installer forums (buyer-voice, 2024-2025).

The Koven All-Electric Heat Pump RTU Line: Models, Tonnage & Specifications

Koven Air builds packaged, all-electric heat pump rooftop units for commercial, industrial, and institutional buildings, engineered around two design priorities that come straight from the pains above: cold-climate heating capacity and coil/cabinet durability. The line spans light-commercial DOAS-integrated units through large-tonnage rooftop heat pumps that reach into the 24-40RT band where the major U.S. brands’ all-electric heat-pump offerings thin out.

Koven heat pump RTU — representative model specifications

The Koven All-Electric Heat Pump RTU Line

SYS_OPT: EVI ON

Specification	DOAS-025HPB (all-electric HP)	Large Rooftop DX Heat Pump
Cooling capacity	85 kW	120 kW (34 RT)
Heating capacity	92 kW	135 kW
Airflow	12,000 m³/h	18,000 m³/h
External static pressure	350 Pa	350 Pa
Refrigerant	R-32 (GWP 675)	R-410A (legacy band)
Compressor	Daikin PM-sync VFD scroll, 10–100%	Scroll VFD, 30–100%
Rated efficiency	IPLV(C) 9.2 · COP 3.6	Cold-climate optimized
Controls	Siemens PLC + 7″ touchscreen, BMS-ready	BMS/BA integration
Filtration	G4 + F7 (PM2.5 ≥ 90%)	G4 + F7
Sound	≤ 62 dB(A) @ 1 m	Low-noise scroll
Heating floor	EVI vapor injection — operation to −30 °C (−22 °F), intelligent defrost

Why the hardware choices matter to the buyer pains

Durability engineering

Every Koven heat pump RTU uses hydrophilic aluminum fin with inner-grooved copper tube (raising heat-exchange efficiency ~15%), a double-wall insulated cabinet, and hot-dip galvanized plus electrostatic-spray corrosion protection – a direct response to the coil-leak and cabinet-corrosion failures that retire competitor units early. Units are built on 23 sheet-metal precision lines with 400-point traceability and a 24-hour aging test before shipment.

Cold-climate refrigerant cycle

Heating capacity at low ambient comes from enhanced/economized vapor injection (EVI) – a secondary refrigerant circuit that sub-cools liquid refrigerant and injects vapor into a mid-cycle port of the scroll compressor. This is a mature, patented technique: recent filings such as US20230271481A1 (simultaneous vapor and liquid injection) and EP4679006A1 (rooftop-mounted economized-injection heat pump) describe the same economizer-plus-injection architecture Koven uses to hold capacity as outdoor temperature drops. Peer-reviewed testing shows EVI improves cold-climate thermal performance by roughly 4-6% over a non-EVI air-source heat pump.

Explore the full range – rooftop units, dedicated outdoor air systems, and heat pump chillers – or jump to the Cold-Climate COP Ladder to see measured performance across the full temperature range.

What separates engineering from a catalog is getting the right unit right: An over/under-sized rooftop heat pump short-cycles or over-works the resistance heat – the stealthy, operation-boosting risk for that 34 ton job. Koven Air sends every unit matched to a building-specific load calc, in-house tested on site for 24 hours before shipping. One-size-fits-all, or engineered-to-spec for your machine shop, cleanroom, or warehouse in any 3 to 34 ton size. We don’t guess; we build.

Sources: Koven Air product & project documentation (first-party); USPTO/EPO patent record; Energy for Sustainable Development (Elsevier) EVI study.

Cold-Climate Performance: The Koven COP Ladder (+7 °C to −30 °C)

The Front-loaded Answer: Can it heat when it’s cold without 100% back-up heat? Yes. University of Illinois EnergySense: Cold-climate heat pumps require sized, not 100%, supplemental heat and produce a COP over 1.75 at 5F – 175% of the energy consumed and better than a 92%-efficient gas furnace. Outdated technology gives the perception that “heat pumps don’t work below 30F”; modern low-ambient units produce substantial heat to 0F and many operate at 15-20F with only a 30% reduction in output.

QA PASSED

Why Buyers are Skittish

The reason the buyers remain nervous is because few manufacturers ever publish a COP vs. temperature curve. A standard COP rating can’t guarantee cold climate performance; AHRI’s residential low-temperature benchmark is at 17F and its commercial ratings (AHRI 340/360) address cooling, not deep-cold heating. Specify confidently only when the manufacturer shares its own data for low temperature operation. Here’s Koven’s data at the low temperature boundary of its design specifications, collected from production units:

Honest engineering note:

COP declines with temperature — that is physics, and any vendor claiming a flat curve is selling marketing. Below its EVI floor, or during defrost, a Koven all-electric unit engages electric supplemental heat, not a gas burner. “All-electric (no gas)” is not the same as “no supplemental heat.” The right design question is the balance point: the outdoor temperature below which supplemental heat engages, sized to your building’s design day — not a blanket 100% backup that inflates electrical service and masks a failing heat pump behind a 3× power bill.

The Koven Cold-Climate COP Ladder — measured heating COP vs. outdoor air temperature (return air 21 °C / 70 °F; supply 30–45 °C)

Outdoor temp (°C)	Outdoor temp (°F)	Measured heating COP	Operating mode
+7	45	4.0 – 4.2	Standard heating
0	32	3.5 – 3.7	Standard heating
−5	23	3.0 – 3.2	EVI engaged
−10	14	2.7 – 3.0	EVI engaged
−12	10	2.5 – 2.8	EVI + intelligent defrost
−15	5	2.3 – 2.5	EVI + intelligent defrost
−18	0	1.7 – 2.1	EVI, capacity managed
−20	−4	1.6 – 2.0	EVI, capacity managed
−30	−22	Operational floor	EVI limit; sized supplemental engages

How much EVI matters compared to a standard unit (whose COP curves the DOE provides and which drops to 35-40% of capacity at 5F) is obvious: Koven maintains COP of 2.3-2.5 at 5F, and goes far beyond where a standard unit would cease to contribute heat.

Independent confirmation from the standards: the DOE/ENERGY STAR Cold Climate program, a residential and light-commercial benchmark, requires at least 70% of rated capacity and COP above 1.75 at 5 °F. Commercial packaged RTUs have no equivalent federal cold-climate certification yet; DOE’s annualized cold-climate heating metric (IVHEC) does not take effect until 2029. Koven’s EVI cycle is engineered to clear it, which is why the NREL ComStock model’s default 0 °F compressor lockout does not describe a true EVI unit that keeps running to −22 °F. ENERGY STAR Cold Climate criteria (residential/light-commercial, v6.1) & NREL Technical Report NREL/TP-5500-85390

For context behind these numbers, look up the DOE’s own reference on ENERGY STAR heating & cooling performance and the NREL commercial HP-RTU modeling report.

This is where an honest manufacturer stands apart from a wishful one. Many an engineer finds themselves on the other side of the purchase agreement looking at a 40% capacity deficit on their design day – that shortcoming which appears only in January – from their trust in a single 47 F COP number. Because Koven Air’s EVI cycle is developed and tested on our own in-house precision production lines, not just rated once and extrapolated, we can quantify the entire curve. Field tested on cold climate application at running temperatures down to 20 C and 30 C, it gives any school or government the real numbers needed, not a marketing curve.

Sources: Koven measured COP dataset (first party); ENERGY STAR Cold Climate v6.1; U.S. DOE energy-saver COP reference; NREL/TP-5500-85390; University of Illinois EnergySense.

All-Electric vs. Hybrid Dual-Fuel Rooftop Units: The Comparison Matrix

The decision fork that separates heat pump rooftop unit projects most sharply is all electric versus a dual-fuel hybrid with a gas back up system. Most “cold-climate” solutions from legacy manufacturers-like the dual-fuel WeatherMaster-class equipment or a recent electrification white paper from Trane-include a gas furnace in the box. That makes a school or facility comfortable on the coldest days, but it also keeps the gas line, the combustion emissions and the code exposure. The all-electric route eliminate all three, but requires genuine low ambient heat pump capacity and adequately sized electrical service. Here’s the honest comparison of both options dimension by dimension.

All-Electric vs. Hybrid Dual-Fuel Heat Pump RTU — decision matrix

Dimension	Koven All-Electric HP RTU	Hybrid Dual-Fuel HP RTU	Legacy Gas/Electric RTU
Primary heat source	Reversible heat pump (EVI)	Heat pump + gas furnace	Gas furnace only
Cold-climate floor	−30 °C / −22 °F	Gas below balance point	n/a (combustion)
Supplemental / backup	Sized electric resistance	Gas burner	None (gas is primary)
On-site combustion emissions	Zero	Reduced (partial gas)	Full
Gas infrastructure	None — line can be cut	Required	Required
Refrigerant	R-32 (GWP 675)	Varies	R-410A legacy
Electrical service impact	Higher — size to design day	Moderate	Lowest
Defrost handling	Intelligent, sensor-based	Gas covers defrost	n/a
Incentive eligibility	Strongest (full electrification)	Partial	Weakest / phasing out
Best-fit climate	Mild to cold (with sizing)	Extreme-cold / dirty grid	Legacy replacement only
Decarbonization path	Complete	Transitional	None

All-Electric vs. Hybrid Dual-Fuel Rooftop Units

Infrastructure Details & Specifications

Interestingly, the upfront equipment premium for a heat pump is only modest, but electrical infrastructure upgrades are often where the real cost lie. An engineering manager at AAON notes that the electric-strip backup required “can double the amps” of a gas-back up heat pump, which can force expensive panel and service upgrades from the utility provider.

This is precisely why Koven Air’s EVI performance matters in a commercial context-the lower you can push the heat pump capacity before it’s needed, the smaller you can make your resistance back-up system and its corresponding amp draw, and therefore, the smaller your service upgrade will be.

DOE modeling on the all-electric version of the unit clearly demonstrates the geography dependent nature of the project economics, projecting ~27% utility bill savings for a school in San Francisco versus about 25% in Minnesota, largely dependent on the local heating load, grid mix and electricity rates.

DOE guidance is clear that buildings in sustained sub-20 °F climates on a fossil-heavy grid can be a better fit for a dual-fuel unit. Koven will tell you when your climate zone and grid favor that path rather than oversell all-electric — because a heat pump RTU specified against the wrong balance point is how buyers get burned.

The Better Buildings Heat Pump RTU Considerations guide offers side-by-side comparisons of these issues from the perspective of the U.S. DOE.

It’s a design choice between the two, not brand choice — and it’s expensive to make the wrong one. Since electric service upgrade, not the equipment, is the sleeper cost to make a 25-ton conversion balloon, Koven Air bases supplemental element sizing on your climate zone so that an all-electric job doesn’t force an unnecessary panel upgrade. All our recommendations are supported by the same in-house engineering and test data that’s behind the COP ladder. Whereas catalog vendors push a single architecture, a commercial or institutional application in the 10-ton to 34-ton range receives a matched call.

Sources: U.S. DOE Better Buildings Heat Pump RTU Considerations; ACHR News (AAON engineering commentary); Trane Technologies electrification white paper (dual-fuel framing).

Proven Results: Gas-to-Electric Decarbonization Case Studies

Specifications earn a shortlist; results earn the order. Koven all-electric heat pump RTUs are now providing full-building comfort to actual institutional and industrial sites, displacing gas boilers and water-cooled chillers with outcomes matching independent US deployments at scale.

Case Study, Government Office Complex, 12,000 m² (gas boiler + chiller → 8× DOAS-025HPB)

82.6% CO₂ reduction
(359.1 t → 62.6 t/yr)

35.2% Energy
savings

3.2 yr Simple
payback

9.2 IPLV(C)
measured

This figure come from a specific gas-boiler-and-chiller replacement, not a general average; building payback depends on the application load, utility tariff and your climate.

Case Study, Industrial Park, 42,000 m²

(18 all-electric rooftop heat pumps)

In an industrial park, located in the northern climate, eighteen Koven rooftop heat pumps did full heating load at a stable 20C without any supplemental electric heat, completed in less than 45 days (approximately 60 percent less than the time needed to replace the system) with annual energy savings of 28 percent (28%) and avoided approximately 920,000 kWh per year, with PM2.5 indoors below 35 g/m.

Independent corroboration at portfolio scale:

the Los Angeles Unified School District, a U.S. DOE Better Buildings case study, has replaced 65% of its decentralized gas HVAC across 13,500 buildings with electric heat pump rooftop units, cutting heating-system emissions 33% on average, saving $139,196 per month, and projecting lifecycle costs 12% lower than the gas units they replace. LAUSD itself reports that larger units serving gyms and auditoriums “await larger commercially available heat pumps”precisely the 24–40 RT gap Koven’s large-tonnage line fills.

U.S. DOE Better Buildings Solution Center, LAUSD Heat Pump Rooftop Units case study

Independent evidence from another study done in eight small commercial buildings including two cold-climate locations in Montana showed total energy use reduction of 61% and emissions reduction from gas-fired buildings to be between 74 percent and 90% utilizing heat pump and DOAS retrofit; proving it applies outside mild-climate regions. You can read a U.S. Department of Energy Better Buildings Solution Center description of this program here and see Koven’s Commercial HVAC Case Studies.

These results are no fluke – these are byproducts of a controlled build. Any case study you can’t reproduce is an undisclosed overseas risk – which is why Koven’s numbers stand up; every one is built with 400-point traceability and a 24-hour burn-in test on our own production lines. Unlike a superficial, meaningless reference, the operator of a 25 ton office or a 34 ton industrial hall can ask to see the raw commissioning data behind our 42,000 m and 12,000 m deployments.

Sources: Koven Air project records (first-party); U.S. DOE Better Buildings (LAUSD); NEEA/RDH Building Science small-commercial pilot.

Integrated Ventilation & Indoor Air Quality: Heat Pump RTU + DOAS

A heat pump rooftop unit goes beyond simply replacing the heating source – if it’s done right, it fixes the ventilation problem that was the unintended byproduct of an oversized, legacy rooftop. The Koven DOAS-025HPB is a Dedicated Outdoor Air System that effectively decouples ventilation from space conditioning, allowing the unit to humidify and temper 100% of outdoor air according to code without over-cooling the building.

What the DOAS design delivers

Ventilation comes first

– all outdoor air rates are sized in accordance with ASHRAE Standard 62.1, which serves as the baseline for commercial ventilation design.

Air quality is next

– thanks to a G4 pre-filter and an F7 fine filter, we capture 90% of the PM2.5 in the outdoor air. CO demand controlled ventilation also modulates fresh air delivery based on occupant load rather than being on full throttle.

The value of right-sizing

– By separating ventilation from air conditioning, the NEEA pilot buildings were able to reduce their installed cooling from 95 tons down to 32 tons. This means no more wasted energy cooling air that’s just being brought in to serve your occupants.

Consistent Humidity control

– The PM-sync VFD scroll modulates 10-100%, keeping the supply dewpoint right where it should be without the constant cycling you find in single stage RTUs.

Indoor Air Quality

– Ventilation and filtration are what decide indoor air quality. The EPA’s guidance for indoor air quality makes clear the link between healthy ventilation and productivity, and the DOAS system is the best way for a rooftop unit to achieve it. Let’s pair the DOAS-025HPB with our rooftop heat pump line for a complete one-stop-shop ventilation solution.

Ventilation determines whether a rooftop retrofit is energy-efficient

– The critical mistake, and hidden energy loss, comes when you try to cram fresh air into an oversided cooling coil which can waste 30-40% of the cooling load. Koven Air solves the problem by creating a standalone, purpose-built DOAS which we burn-in-test alongside the heat pump on the same production lines as the rooftop units. Medical facilities, cleanrooms, and even a 25-ton office floor will achieve a 5°C supply outdoor air temperature without any over-cooling or short cycling, unlike a traditional packaged RTU which has to over-cool to dehumidify.

Sources: ASHRAE Standard 62.1 (ventilation for acceptable IAQ); U.S. EPA IAQ program; Koven DOAS-025HPB specification (first-party); NEEA/RDH right-sizing data.

Standards, Ratings & Refrigerant Compliance for Heat Pump RTUs

Commercial heat pump RTUs: what you should be seeing in specifications

The first thing any credible commercial RTU specification sheet should tell you is that it follows three distinct, interconnected rules you should be looking for. AHRI 340/360-2022 is the test method; ASHRAE 90.1-2019 is the minimum design efficiency level; and 10 CFR Part 431, Subpart F is the federal law making that level binding. On refrigerants, the EPA's Technology Transitions rule capped new Equipment GWP at 700 - which is why Koven leads with R-32 (675 GWP), not R-410A (2,088 GWP).

Ratings discipline, what we claim and what we don't

Koven publishes its AHRI 340/360-2022 IEER/EER and COP on spec sheets and backs up claims with performance curves for engineers. We won't advertise an AHRI-directory listing that doesn't exist. Nor do we fall for the trap outlined by University of Illinois’ 2023 Heat Pump Performance report : an AHRI low temperature rating point for residential AC (17 F, AHRI 210/240) isn't equivalent to a cold-climate performance statement for a commercial product. In the opposite direction, Commercial AHRI 340/360 ratings only address IEER/EER for cooling, not deep cold heating (IVHEC for cold-climate heating performance only becomes required in 2029). But rating points aren't performance curves-hence the measured data at 20/30 C from the COP Ladder above that answers an engineer’s question.

Governing standards & refrigerant rules for commercial heat pump RTUs

Rule	What it governs	Relevance to a heat pump RTU
AHRI 340/360-2022	Performance rating method (IEER, EER)	The basis for any published efficiency number
ASHRAE 90.1 §6.8	Minimum equipment efficiency (design floor)	The efficiency the unit must meet or beat
ASHRAE 62.1	Ventilation for acceptable IAQ	Outdoor-air basis for the DOAS variant
10 CFR 431 Subpart F	Federal energy-conservation standard	Legally binding commercial HP/AC floor
EPA HFC Technology Transitions	700 GWP limit (Jan 1, 2025)	Drives R-410A → R-32/R-454B
ENERGY STAR Cold Climate v6.1	≥70% capacity & COP>1.75 at 5 °F	Residential/light-commercial benchmark; no commercial-RTU equivalent yet (DOE IVHEC 2029)

On the refrigerant transition: the EPA’s Technology Transitions rule capped new residential and light commercial stationary equipment GWP at 700, effective January 1, 2025. New, larger commercial equipment phase on at later dates. So the move to R-32 (675 GWP) and R-454B (466 GWP), from R-410A (2,088 GWP), will be mandatory across all new commercial HVAC applications within the next several years. And the federal framework is solidified in 10 CFR 431.

Standards are where overclaims get tested -by engineers first, and by Google second. Many commercial RTU specs fail engineers because of a non-existent AHRI-directory number, or an unsupportable, warm 47°F rating passed off as “cold climate.” Koven Air will never present a listing we cannot justify. We test, quantify, and certify against the AHRI 340/360 standard, publishing every bit of measured performance data - complete and verifiable through our in-house tests. While other suppliers simply list the performance they *assume* you want, an aerospace or data center client needing 25 tons of compliance floor is guaranteed to receive a defensible package.

Sources: AHRI 340/360-2022; ANSI/ASHRAE 90.1 & 62.1; 10 CFR 431 Subpart F (eCFR); EPA HFC Technology Transitions rule; ENERGY STAR.

Tonnage Selection, Total Cost & Incentives: The Procurement Framework

The last mile of selecting the correct RTU size and justifying the costs involves two essential tools: The Tonnage-to-Building Selection Map and The Gas-to-Electric Decarbonization ROI Model.

01
Tonnage Selection Map
02
Decarbonization ROI Model
03
Lead Time & After-Sales

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The Tonnage-to-Building Selection Map

Indicative heat pump RTU sizing by application

Building type	Typical zone load	Indicative HP RTU size	Configuration note
Small retail / branch office	3–5 RT	Single packaged HP	All-electric, drop-in replacement
School classroom wing	5–10 RT	Multiple HP RTUs	DOE-identified drop-in candidate band
Medium office floor	10–15 RT	HP RTU + DOAS	Decouple ventilation
Government / institutional	15–25 RT	DOAS-025HPB clusters	See 12,000 m² case
Light industrial / warehouse	25–34 RT	Large rooftop HP (120 kW)	High airflow, high ESP
Large industrial park	34–40 RT+	Multi-unit large HP	See 42,000 m² case
Gym / auditorium	> 25 RT single-zone	Large-tonnage HP	The band legacy brands thin out in
Data-center support space	Project-specific	Custom AHU/RTU	Coordinate with process cooling
Multi-tenant mixed-use	Blended	Mixed HP RTU + DOAS	Zone-by-zone balance point

The Gas-to-Electric Decarbonization ROI Model

Financial justification & incentives

The Cost case is stronger than sticker price suggests. The heat pump premium over a comparative base unit ranges $74-650 per ton, depending on size and efficiency class (CalMTA, 2025) - a fraction of the ~$5,900/ton fully installed price. The payback on our 12,000m² government project was 3.2 years - well within the 1-3 years considered a good return for most commercial users, who rarely exceed 5 years. Utility rebates also improve it.

Incentives — the honest, dated picture (verify before you rely on it): The federal Section 179D commercial-buildings deduction (historically up to ~$5.00–$6.00/ft², and up to $5.81/ft² with prevailing-wage compliance) is terminated for construction that begins after June 30, 2026 under the One Big Beautiful Bill (IRS FS-2025-05). Projects that broke ground on or before that date may still claim it; new starts should build the case on MACRS accelerated depreciation, Investment Tax Credits for paired solar/storage, and utility rebates (e.g., PG&E, SCE, Duke, Xcel, ConEd, and programs like Focus on Energy running through 2026) rather than on 179D. Incentive eligibility varies by location, utility, and code — confirm current status with a qualified tax and energy professional.

Lead Time & After-Sales

The answer to the overseas-manufacturer objection

The forum is explicit about service and parts availability: the heat pump price premium matters less than brand support and spare parts readiness, even top brands can strand owners for months with backorders. We have addressed that by offering lifetime free tech support, paid on-site commissioning, and a 35-country manufacturing base with 400-point unit traceability; if you need a part, you know what build it belonged to, without the guesswork. Check current federal incentive status at the IRS 179D page before developing a cost case, then contact our sales engineering for a build-to-project quotation.

Getting tonnage wrong is the most expensive mistake in the project, oversize and you short-cycle a 40 ton unit, undersize and you strand 20% of the load on resistance heat. Because sizing drives the whole ROI, our engineering team sizes against your actual design day rather than a rule of thumb, and backs every 3 ton to 40 ton selection with in-house test data. Unlike a distributor working from a catalog, an industrial or institutional application gets a build-to-order match. Request the tonnage worksheet and a matched gas-to-electric ROI estimate for your building.

Advanced Heat Pump RTU Engineering & Estimation Tools

Gas-to-Electric Heat Pump RTU ROI Estimator

A transparent first-pass estimate of annual savings and simple payback when replacing a gas rooftop unit with an all-electric heat pump RTU. Adjust the inputs to your building.

Calculate ROI

Heat Pump RTU Tonnage & Model Selector

A quick indicative sizing from building type and area. Use it to frame a shortlist — a stamped load calculation still governs the final selection.

Select Model

Cold-Climate COP & Supplemental-Heat Lookup

Drag to an outdoor temperature and read the measured heating COP from the Koven Cold-Climate COP Ladder, the operating mode, and whether sized supplemental heat is likely to engage.

Lookup COP

FAQ: Heat Pump RTU Questions Engineers and Buyers Ask

A heat pump RTU is a packaged Rooftop Unit with a single refrigerant circuit that cools and heats a building. The unit uses a heat pump instead of a gas furnace for heat and is mounted on the roof of a building, similar to a typical gas and electric packaged rooftop unit, but it runs exclusively on electricity and doesn't produce combustion by-products on-site.

Yes. Cold-climate heat pump RTUs using EVI vapor injection still have useful heat capacity below freezing-Koven units are measured running down to -30°C (-22°F). Residential and light-commercial ENERGY STAR Cold Climate benchmarks require 70% of capacity at 5°F (0°F), with COPs > 1.75. Commercial packaged RTUs are constrained by the same physics even though commercial cold-climate performance labels are just developing (DOE’s IVHEC metrics, set for 2029). What differs in the cold is efficiency-the COP goes down-which can be handled by the appropriate size supplemental heat.

Yes, sized supplemental heat-not full, 100% backup. “The difference between backup and supplemental heat,” says the University of Illinois EnergySense center, “is the size of the element-backup supplies 100% of the cooling/heating load in case of failure of the heat pump, and supplemental provides a portion of the load only during the hours that fall below the balance point.” In an all-electric setting, that supplemental means electric resistance- “all-electric, no gas line” means all-electric equipment, plus supplemental electric resistance, not supplemental gas heat.

The upfront heat pump premium is quite modest-an additional $74-$650/ton compared with a comparable base gas unit (for the 5-40-ton ranges discussed here) on top of a typical all-in cost of $2,500/ton or so (based on $5,900/ton in 2025 US market data). The much larger variable in installed cost is electrical service-since all-electric backup requires increased electrical service capacity, a tighter cold-climate COP curve (which makes the supplemental less of an issue) will actually reduce the overall installed price. The payback on this is generally in the 1-3 year range, assuming electricity prices are reasonable.

The line covers everything from light-commercial, DOAS-integrated systems, through large 34-ton cooling capacity (120 kW) rooftop units and multi-unit buildings up to 40 tons or more. That also include single-zone units greater than 25 tons, a size range where most of the leading US brands stop their all-electric heat pump offerings-a gap that DOE tracked projects like Los Angeles Unified School District have been wanting to fill.

Not necessarily. An RTU (rooftop unit) is any self-contained packaged system located on a roof that provides HVAC-whether it’s heat pump functionality depends on whether it reverses to provide heating. A conventional gas/electric RTU cools via a refrigeration cycle, but provides heat via an on-board gas furnace, so it’s not a heat pump. All of the Koven units in this series are true heat pumps.

RTU stands for Rooftop Unit, an all-inclusive packaged HVAC unit located outside on the roof-as opposed to an AHU (air handler unit), which is typically indoors and moves air but isn't self-contained. A heat pump RTU includes everything needed to cool and heat in a single cabinet; an AHU is part of a larger “built-up” HVAC system and depends on external equipment for heat and cool.

On VRF vs RTU: A variable refrigerant flow (VRF) system circulates refrigerant among multiple small indoor fan coil units to control temperature on a zone-by-zone basis, whereas a heat pump RTU conditions a larger, open-plan space from one rooftop unit. RTUs are generally simpler to maintain and more easily replaced than vrf systems at end of service life. VRF’s fine zoning capabilities come at a greater cost and complexity. For open plan retail spaces, schools, warehouses, and municipal offices, an rooftop packaged heat pump unit often presents a simpler and more serviceable path to electrification.