The Zero Homes Blog
Field Notes
What we’re learning from designing the systems, researching the rebates, and installing jobs across Colorado homes.
Will a heat pump keep your house warm at 5°F? Yes, and here's the math.
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Do heat pumps work in cold weather? What the field data says
Yes. In DOE field tests across 22 homes, cold-climate heat pumps kept heating down to -15°F with little backup heat.
Cold climate heat pump: what qualifies, and what to look for in Colorado
Holds 70%+ of its capacity at 5°F.
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Part 3 · The mathHeat pump COP by temperature: what the efficiency numbers actually mean
2.5× the heat of a gas furnace at 5°F.
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Part 4 · The January billHow much electricity does a heat pump use in a Colorado winter?
About 33 kWh a day in January.
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Heat pump vs furnace: which one makes sense for a Colorado home?
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Is a dual-fuel heat pump worth it in Colorado?
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What size heat pump do I need? Sizing for a Colorado winter
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How to choose a heat pump installer: what actually matters
Manual J before any quoteLatest
Every guide, filterable
Narrow by topic or by where you live. Newest first. New this fall: our Colorado winter series.
Winter series · Cold weather
Do heat pumps work in cold weather? What the field data says
Yes. In DOE field tests across 22 homes, cold-climate heat pumps ran at a COP of 1.5 to 4.5 from -15°F to 65°F with little backup. The Colorado read.
Oct 27, 2026
Winter series · Efficiency
Heat pump COP by temperature: what the efficiency numbers actually mean
COP runs about 4.0 at 47°F and 2.0 at 5°F for cold-climate models. An 80% gas furnace is 0.8 at any temperature.
Oct 27, 2026
Winter series · Running cost
How much electricity does a heat pump use in a Colorado winter?
About 4,900 kWh a year to heat a typical Denver home, peaking near 33 kWh a day in January. Month by month, on Xcel's rates.
Oct 27, 2026
Winter series · Furnace
Heat pump vs furnace: which one makes sense for a Colorado home?
A cold-climate heat pump runs about 15% ($130 a year) cheaper than a 15-to-20-year-old gas furnace and AC on Xcel's rates. The math, shown.
Oct 27, 2026
Winter series · Dual fuel
Is a dual-fuel heat pump worth it in Colorado?
About $70 (10%) a year cheaper than a heat pump alone and $140 (17%) cheaper than an 80% furnace and AC in Denver. When it's worth it.
Oct 27, 2026
Winter series · Sizing
What size heat pump do I need? Sizing for a Colorado winter
Square footage gets heat pump size wrong. Size to your county's design temperature with a Manual J load calculation. Here's how to check a quote.
Oct 27, 2026
Winter series · Equipment
Cold climate heat pump: what qualifies, and what to look for in Colorado
A cold-climate heat pump holds 70%+ of its capacity at 5°F and runs to -13°F. What qualifies, what it costs to run, and what fits Colorado.
Oct 26, 2026
Program · Mountain CO
Xcel's Mountain Energy Project: what mountain homeowners can get
Xcel's Mountain Energy Project pays up to $7,500 per heating ton for a heat pump in eight Colorado mountain towns, and the largest amounts go to homeowners who replace before the equipment fails.
Aug 28, 2026
Program · Aurora
Xcel's Aurora F-3 Project: what it covers and who qualifies
Xcel's Aurora F-3 Project covers 100% of project cost, up to set caps, on heat pumps, insulation, and air sealing inside one Aurora boundary. Here's who qualifies.
Aug 28, 2026
Heat pump vs. everything else
| If you are weighing | The short answer | Guide |
|---|---|---|
| Heat pump vs. gas furnace | A cold-climate heat pump runs about 15% (about $130 a year) cheaper than a 15-to-20-year-old furnace and AC on Xcel's rates. The old furnace only wins December through February, by about $39 total. | Read |
| Cold-climate vs. standard heat pump | A cold-climate unit holds 70%+ of its capacity at 5°F and runs to -13°F. A standard unit often hands off to resistance strips near 25°F. On the Front Range, that's the whole difference. | Read |
| Dual fuel vs. all-electric | Dual fuel runs the furnace about three months a year. With a newer 80% furnace it costs about $70 (10%) less a year than a heat pump alone. Worth it if your furnace has life left, or in mountain-cold homes. | Read |
| Heat pump vs. air conditioner | Same outdoor box, same summer efficiency. The heat pump adds winter heating for a modest equipment premium, which is why replacing a dying AC is the cheapest moment to switch. | Read |
| Heat pump vs. electric baseboard | Baseboard converts electricity to heat one-for-one. A heat pump uses about a third of the electricity for the same house, so this swap produces the largest bill drop on the list. | Read |
| Ducted vs. ductless | If usable ducts exist, use them. Additions, finished attics, and one stubborn room are ductless jobs. | Read |
| Mini-split basics | What a mini-split actually is, where a single head makes sense, and when you need a multi-zone system. | Read |
| Gas vs. electric water heater | A heat pump water heater beats both on running cost and is rebated separately from the HVAC system. | Read |
Which programs are open, and where
| Program | Territory | Why it matters | Guide |
|---|---|---|---|
| Xcel Energy statewide | Colorado | Stepped down October 1, 2026: $1,500 per heating ton for cold-climate systems (was $2,250). Still the largest layer for most Front Range homes. | Read |
| Xcel Mountain Energy Project | Colorado mountain counties | Per-ton payments well above the statewide program, for a limited set of counties. | Read |
| Xcel Aurora F-3 | Aurora | A neighborhood program that runs separately from the statewide rebate. | Read |
| Xcel Residential Retrofit | Colorado | The older retrofit path, still named on quotes and invoices. | Read |
| Denver region: Power Ahead Colorado | Denver metro | Up to $1,500 for a cold-climate heat pump, no income limit. Replaced Denver CARe, which closed in May 2025. | Read |
| Tri-State: Electrify and Save | Colorado co-op territory | Covers the areas Xcel does not serve. | Read |
| Mountain View Electric | El Paso and Elbert counties | Co-op rebate, separate application. | Read |
| Gunnison County Electric | Gunnison County | Co-op rebate, separate application. | Read |
| San Luis Valley REC | San Luis Valley | Co-op rebate, separate application. | Read |
| Great River Energy | Minnesota metro co-ops | The off-peak electric rate is often worth more than the rebate itself. | Read |
| CCEF on-bill repayment | Colorado | Puts the balance on the utility bill instead of a loan. | Read |
Heat pumps 101
The heat pump guide: how the equipment works, the types, and what the ratings on the spec sheet actually mean.
What makes a heat pump cold-climate: the 5°F test, and how to read it on a spec sheet.
COP by temperature: what "300% efficient" means, and why it drops as it gets colder.
What size heat pump do I need: sizing to your county's design temperature, not square footage.
How to choose an installer: the questions that separate a real load calculation from a guess.
Signs it is time to replace the furnace: the repair-or-replace math, before the emergency.
Hot upstairs, cold downstairs: why it happens and which fixes hold.
Upgrading HVAC without a home visit: how a remote design and a fixed quote work.
Heat pumps with $0 down: on-bill repayment, explained.
Common questions
Heat pump questions homeowners actually ask
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