Find top-rated installers near you

A Manual J calculation is the industry-standard way to size a heat pump to your actual home — its insulation, windows, and layout — not just to whatever was there before. An installer who skips it and quotes a size "because that's what you had" is guessing, and an oversized or undersized heat pump runs less efficiently and wears out faster.

Source: EnergySage

A high-efficiency heat pump only performs to spec if it's commissioned correctly — refrigerant charge and airflow across the coil verified after installation, per ENERGY STAR's Quality Installation guidelines. Ask how the installer checks this, and ask to see the numbers, not just take their word for it.

Source: EnergySage

Ductless (mini-split) heads are visible on the wall or ceiling — ask exactly where they'll go and see a photo of a similar install before you commit, not just a brochure shot.

Source: EnergySage

Ask for the license number so you can check it's active, and ask to be named as additional insured on their liability coverage during the job. A legitimate installer will produce both without hesitation.

Source: EnergySage

Rebate stacks and paperwork requirements vary a lot by program — some installers submit the paperwork for you, others leave it to the homeowner. Ask which applies before work starts, and cross-check whatever they tell you against the official rebate figures on your city's rebate page here on HomePowerRebate.

Source: EnergySage

NABCEP (North American Board of Certified Energy Practitioners) certification is the closest thing solar has to an industry credential. Ask for it, plus a state license number and proof of bonding and insurance, and ask how many installations of a similar size the crew has actually completed.

Source: EnergySage

Get the complete contract, not a summary, and read the warranty terms, payment schedule, and cancellation clause carefully. Watch specifically for language about what happens if equipment becomes unavailable or pricing changes mid-project.

Source: EnergySage

Most reputable installers handle permits and interconnection paperwork as part of the job. Confirm that's included and ask roughly how long that process takes in your city before your system can actually turn on.

Source: EnergySage

Ask separately about the panel manufacturer's warranty, the inverter warranty, and the installer's own workmanship warranty — they're rarely the same length, and a longer workmanship warranty is a signal the installer expects to be around to honor it.

Source: EnergySage

Ask the installer to walk through why they picked a specific battery's power rating and storage capacity for your household — it should be based on your actual usage and backup goals, not just what they happen to stock.

Source: EnergySage

If subcontractors are involved, ask what portion of the job they'll handle and what oversight the company you're paying actually has over their work — and, ultimately, who is on the hook if something goes wrong.

Source: EnergySage

Battery manufacturers run their own installer certification programs. Ask if the crew is certified on the exact model you've been quoted, not just "batteries in general."

Source: EnergySage

Confirm both licensing and that the crew doing the actual blowing or spraying is trained on that material — attic blown-in, spray foam, and batt insulation are different skills.

Source: ENERGY STAR

Adding insulation on top of unsealed air leaks wastes a lot of its value. The best insulation crews treat air sealing as a standard part of the job — ask directly whether it's included or billed separately.

Source: Insulation Contractors Association of America

Blown-in insulation settles over time. Ask if the contractor guarantees a minimum depth and will come back to top it up if it settles below spec within the warranty period.

Source: Insulation Contractors Association of America

Older attics (pre-1930s especially) can hide outdated wiring or existing damage. Ask the contractor to flag anything like that before covering it with new insulation, and get it in writing that they will.

Source: ENERGY STAR

Not every plumber or HVAC tech has hands-on experience with heat pump water heaters specifically — ask directly, since sizing and placement work differently than a standard gas or electric tank.

Source: ENERGY STAR

Heat pump water heaters pull heat from the surrounding air, so they need roughly 750 cubic feet of space to run efficiently. If yours is going in a small mechanical closet, ask whether louvered doors or ducting the exhaust will be needed.

Source: Massachusetts Clean Energy Center

Ask whether your current tank was over- or undersized for your household, since that affects whether to size up or down on the replacement — when you're between two sizes, a larger heat pump water heater is usually the more efficient pick.

Source: Massachusetts Clean Energy Center

Most systems installed after 1990 with standard 24V controls work fine. Older systems with millivolt controls or gravity furnaces often don't without extra work — ask the installer to check before you buy a thermostat.

Source: ENERGY STAR

Many smart thermostats need a common wire (C-wire) for constant power. If your system doesn't have one, ask whether the installer will add a wire or use an adapter, and which they recommend for your setup.

Source: ENERGY STAR

Ask the installer to run the system through a full cycle after install and show you how to use scheduling and remote controls — a thermostat that's never demonstrated tends to sit on factory settings for years.

Source: ENERGY STAR

General electrical experience isn't the same as EV charger experience — ask for a number, and ask if they're certified by the specific charger manufacturer you're considering.

Source: U.S. DOE Alternative Fuels Data Center

A proper assessment includes reviewing your panel's available capacity before quoting a price — if a panel upgrade is needed, that should show up in the estimate up front, not as a surprise mid-job.

Source: U.S. DOE Alternative Fuels Data Center

Permits and inspections should be handled by the electrician, not left to you. And if there's any chance of a second EV in the household later, ask now whether the install is being sized to support that — it's far cheaper to plan for it upfront than to redo the panel later.

Source: U.S. DOE Alternative Fuels Data Center

ENERGY STAR certification requirements for windows vary by climate zone — a window certified for one region may not qualify (or perform well) in another. Ask the installer to confirm the specific model is certified for where you live, and ask about Low-E coatings and gas fills that affect real-world performance.

Source: ENERGY STAR

Ask whether the company that sold you the windows also installs them, or whether that work is handed off to a sub — and how long that crew has been doing window installs specifically.

Source: ENERGY STAR

These are usually two separate things — a manufacturer's warranty on the glass and frame, and a separate workmanship warranty from whoever installed them. Ask for both in writing before you sign.

Source: ENERGY STAR