Free HVAC Tool
Solar + Heat Pump Calculator
See how your solar panels interact with a heat pump. Coverage gap analysis, monthly net metering breakdown, and 3-way cost comparison using current Xcel Energy rates.
BlueTM
AI Summary
If you already have solar, it was sized for your pre-heat-pump electric usage. Adding a heat pump increases your electricity by 4,000-8,000 kWh/yr, dropping your coverage from ~99% to 55-65%. Net metering credit rollover from summer surplus helps offset winter heating costs, but you'll buy some electricity from the grid. Use the calculator to see your exact numbers.
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The Solar Math
What Changes When You Add a Heat Pump
Your solar panels produce the same kWh regardless. But your total usage increases, which changes the economics.
Coverage Gap: 99% to ~60%
Adding a heat pump increases your electric load by 4,000-8,000 kWh/yr. Your existing solar, sized for pre-heat-pump usage, now covers a smaller share.
Credit Rollover Helps
Summer solar surplus rolls forward as Xcel net metering credits, offsetting some winter grid purchases when heating demand peaks.
Lower Effective Rate
Solar reduces your effective heating rate below the grid rate. The calculator shows your true marginal cost of heat pump operation after solar credits.
Month-by-Month Model
Not an annual average - the calculator runs 12 monthly net metering cycles with real Denver GHI data and credit bank tracking.
Your Solar Was Sized for Gas Heating
When your solar was installed, your gas furnace wasn't part of the electric equation.
The Coverage Gap Explained
Most Colorado solar installations are sized to cover your annual electric bill: baseload appliances plus air conditioning. That typically works out to 6-10 kW for an average home, producing enough to offset 90-100% of your usage. Adding a heat pump shifts heating from gas to electric, adding 4,000-8,000 kWh/year to your total. Same panels, larger load, smaller coverage percentage.
Solar covers ~100% of electric usage. Net metering credits roll over from summer surplus to winter. Your electric bill is near zero. Everything is balanced.
The heat pump adds 4,000-8,000+ kWh/year. Solar now covers 55-65% of the total. You buy the difference from the grid, especially in winter when solar production is lowest and heating demand is highest.
But Net Metering Helps
Under Xcel's net metering policy, summer surplus production banks as credits that reduce your winter bills. Your panels can't directly power the heat pump in January, but the credits you banked in July offset some of those winter grid imports.
- •April-September: solar overproduces, surplus kWh bank as credits
- •October-March: heating demand exceeds production, banked credits reduce your bill
- •Year-end: unused credits reset to zero, no cash value (conservative assumption)
The Seasonal Pattern
Solar production and heat pump demand move in opposite directions.
Why the Effective Heating Rate Matters
The calculator shows an "effective heating rate" that's lower than the grid rate ($0.140/kWh as of 2026-02). This isn't a discount - it's the result of net metering math.
Summer surplus credits reduce your total annual bill. When we isolate just the heating cost (bill with heating minus bill without heating), the per-kWh rate for heating electricity comes out lower than grid because some of that heating load was effectively "pre-paid" by summer solar surplus.
This rate is what the switchover calculator uses when solar is enabled, making the gas vs heat pump comparison more accurate for homes with solar.
Solar + Heat Pump: Planning Sequence
The order you install matters for sizing and economics.
Scenario 1: Already Have Solar
Use "I have solar" mode
The calculator estimates your system size from your pre-heat-pump usage. Adjust if you know your actual kW.
Budget for grid electricity
Your solar was sized under Xcel's cap based on pre-heat-pump usage. The coverage gap shows how much grid electricity to expect.
Scenario 2: Planning Both
Install heat pump first
This gives you actual usage data to size solar correctly. Xcel allows up to 200% of expected consumption for solar sizing.
Size solar to total load
Use "Planning solar" mode to model different system sizes. The month-by-month breakdown shows exactly what each size covers.
Solar still makes sense even with partial coverage
You don't need 100% offset for solar to be worthwhile. Even a system covering 60-70% of your total usage significantly reduces your grid costs through net metering credit rollover. The effective heating rate drops, making your heat pump cheaper to operate than the grid rate alone would suggest.
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Solar + Heat Pump FAQs
Common questions about solar and heat pump interactions in Colorado
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