Frequently Asked Questions

Yes. Every calculator and guide on GreenCalcs is completely free, with no sign-up, no email required, and no storing or selling of your inputs. We're supported by advertising and remain independent — we're not an installer, lead broker or financing company. See our methodology.

Each tool traces its inputs to primary sources — NREL for costs, DSIRE for incentives, the EIA for electricity rates, and the IRS for tax credits — and shows its full formula on the page so you can audit it. Results are good estimates for planning; always confirm specifics with a licensed installer and your tax professional.

No. You can use every calculator without entering an email or phone number, we don't store your inputs, and we never sell your data. This is a deliberate difference from many 'free quote' sites that exist to harvest leads.

If you're replacing a dying furnace or AC, do the heat pump now; if your HVAC is fine, solar can come first. Ideally, size the solar to cover the heat pump's future electric load. Pairing both is one of the strongest home-energy moves — see our heat pump + solar savings math.

A typical residential system runs about $2.50–$3.50 per watt installed before incentives, so a 7 kW system is roughly $17,500–$24,500 before the 30% federal credit brings it down. Costs vary by state, installer and equipment. Estimate yours with the payback calculator.

The Residential Clean Energy Credit (25D) is 30% of the total system cost with no dollar cap, available through 2032 and able to carry forward to future years. It covers solar panels, batteries and geothermal. Full details in our solar tax credit guide.

Most US homeowners see payback in 6–12 years, depending on electricity rates, sunshine, system cost and net-metering policy. After that, the system produces largely free electricity for the rest of its 25–30 year life. Run your numbers with the ROI calculator.

Buying (cash or loan) almost always wins financially: you claim the 30% credit, capture all the savings, and add home value. Leasing forfeits the credit and most of the savings and can complicate a home sale. See our lease vs buy vs loan guide.

Divide your annual electricity use (kWh) by your local production per kW (about 1,200–1,600 kWh/kW/yr), then size the array accordingly. Most homes need 6–11 kW for electricity alone, or more for an all-electric home. See how many panels you need.

Yes — owned solar adds roughly a 4% premium to home value on average, and homes with owned solar tend to sell faster. Leased solar generally does not add value and can complicate sales. See our home value guide.

Most roofs are. The main factors are direction (south is best, east/west still work), pitch, shade, available space and roof age — replace a roof nearing end-of-life first. See our roof suitability guide.

A heat pump moves heat rather than making it, using refrigerant to pull warmth from outside air (even cold air) into your home in winter, and reversing in summer to remove heat and cool the home. Because it moves heat, it delivers 300–400% efficiency — far beyond any fuel-burning system.

Yes. Modern cold-climate (hyper-heat) models maintain capacity and a COP above 2 well below freezing and heat reliably to -15°F or lower. Correct sizing and, in the harshest climates, a backup matter. See our cold-climate guide.

A whole-home air-source heat pump typically costs $12,000–$24,000 installed before incentives, depending on ducted vs ductless, home size and climate. The 30% federal credit (up to $2,000) plus state and utility rebates reduce that. Price yours with the cost calculator.

Air-source heat pumps qualify for the 25C credit: 30% of cost up to $2,000 per year, for models meeting the CEE highest efficiency tier. Geothermal heat pumps get the 25D credit: 30% with no cap. See our heat pump tax credit guide.

Size to a proper Manual J load calculation, not a rule of thumb — oversizing causes short-cycling and poor comfort. As a rough starting point, homes need 2–5 tons (24,000–60,000 BTU/h). Use the size calculator and our sizing guide.

It depends on your climate and ducting. Mitsubishi and Fujitsu lead for cold climates and ductless; Carrier, Trane and Daikin for premium ducted; Goodman, Rheem and LG for value. The installer matters more than the brand — see our brands guide.

Not really. Most outdoor units run at 40–60 dB — about a refrigerator hum or quiet conversation — and variable-speed models are quieter still. Good placement and a low-decibel model keep noise from being an issue. See our noise guide.

Typically 15–20 years, with well-maintained units reaching the top of that range. Because a heat pump runs year-round, regular maintenance — filters, coil cleaning and an annual tune-up — is key to longevity. See our maintenance schedule.

For most homes a heat pump wins, especially if your AC is also aging, since it does both jobs efficiently. Where natural gas is very cheap and winters are harsh, a hybrid dual-fuel system keeps the furnace as backup — see our dual-fuel guide and heat pump vs furnace comparison.

Yes, in most cases. Federal tax credits, HEEHRA rebates, state rebates and utility rebates generally stack. The federal 30% credit is calculated on your net cost after rebates. See our state rebates guide.

An IRA-funded, state-administered rebate program offering up to $8,000 for a qualifying heat pump to income-qualified households (full benefit below 80% of area median income, half at 80–150%). It's paid upfront at point of sale, not as a tax credit.

Use DSIRE (dsireusa.org), the comprehensive ZIP-searchable database of state and utility incentives, plus your state energy office for HEAR status and your utility's website. The state rebates guide maps the major programs by region.

No. The 25C heat pump credit (30% up to $2,000) is non-refundable and doesn't carry forward — you need tax liability that year. The 25D credit for solar, batteries and geothermal (30%, uncapped) is also non-refundable but carries forward to future years.

Yes. Installed in the same year, you claim the 30% solar credit (25D, uncapped) and the heat pump credit (25C up to $2,000, or 25D uncapped for geothermal) together on IRS Form 5695. See our heat pump + solar math.