How to choose a window company

A window quote is two products: the unit and the installation. A low number that names neither one is not a quote you can compare. This guide explains the label ratings the National Fenestration Rating Council prints and the conditions ENERGY STAR publishes. It does not pick a brand and it does not invent an energy savings dollar figure.

During posted hours, use the referral call page for this service. This guide does not display a routing number.

Author: Dial Home Help editorial desk
Editor: Dial Home Help
Updated: October 22, 2026
Policy: Editorial policy

What the NFRC label is measuring

NFRC says its label lets you compare windows, doors, and skylights. U-factor measures how well the product keeps heat from escaping. NFRC states the U-factor scale on that explanation as 0.20 to 1.20, and it says a lower number is better at keeping heat in. Solar heat gain coefficient measures how much solar heat the product lets in. NFRC says low numbers resist solar heat and high numbers allow it, on a scale of 0 to 1. Visible transmittance measures daylight, also 0 to 1, with a higher number letting in more light.

Those ranges are the scales on the label, not a score for a window we sell and not a target this site sets for your house. A lower U-factor is not automatically the right product if you also care about solar heat, light, or condensation. Read the three numbers together. Air leakage is a separate rating on the same label. Use the label in front of you, not a number remembered from an advertisement.

What ENERGY STAR adds

ENERGY STAR says certified windows are made by a partner, independently tested and certified by NFRC, and have NFRC ratings that meet EPA guidelines. It also says the criteria differ by climate zone. A unit that qualifies in one zone is not described by ENERGY STAR as the criterion for every zone. Ask the company which zone they are using for your address and to show the NFRC label for the exact series in the quote, not for a different series with a better number.

ENERGY STAR does not require one frame material. It describes fiberglass, vinyl, aluminum with thermal breaks, wood, and combinations as materials you will see. The material is not a ranking. Ask why they specified the one in the quote, and whether the label you were shown belongs to that frame and that glass together.

Installation is part of the product

A certified unit installed with a crooked opening, missing flashing, or an uninsulated gap will not perform like the label. Ask who employs the installers, whether they are a subcontractor, and who warrants labor as distinct from the manufacturer's warranty on the glass and the frame. Ask what happens to the interior trim and the exterior cladding, and who patches them.

If the house was built before 1978, disturbing paint can be a lead-safe work practice, not a casual scrape. The EPA's renovation, repair, and painting rule requires firm certification for renovations that disturb lead-based paint in pre-1978 housing, and in child-occupied facilities. Ask the company if they hold that certification when the work will disturb painted surfaces in a pre-1978 home. Dial Home Help does not inspect the paint.

What the contract should name

The series, the NFRC ratings for that series, the quantity, the rooms, who installs, how long labor is warranted, and what is excluded. A payment schedule tied to delivery and to completion is easier to read than one large payment on signing. This page does not set the deposit. Get the ratings attached to the contract so a different unit cannot be substituted without a conversation.

If you call from this guide, you reach an independent provider, not a window crew employed by Dial Home Help. They set the price. They may pay Dial Home Help for the introduction. There is no review score on this site to outsource the comparison. Use the label and the contract.

Steps

Ask for the NFRC label of the quoted series. U-factor, solar heat gain, and visible transmittance, for that glass and frame together. The scales are not a price.
Ask which ENERGY STAR climate zone they used. Criteria differ by zone. A label from another series does not count.
Separate the unit from the installation. Who installs, who warrants labor, and how flashing and the gap are handled.
Ask about lead-safe work in a pre-1978 house. The EPA RRP rule covers firms that disturb paint in pre-1978 housing. Ask if it applies to your job.
Attach the ratings to the contract. Series, counts, rooms, and exclusions. The independent provider sets the price.

Questions

Does a lower U-factor always mean the right window?

NFRC says a lower U-factor is better at keeping heat in. Solar heat gain and daylight are separate ratings. Read them together for your climate. This site does not pick a number for you.

Does ENERGY STAR use one national cutoff?

No. ENERGY STAR says the criteria vary by climate zone and that products are certified by NFRC against EPA guidelines.

Who installs the windows if I call?

An independent provider. Dial Home Help does not install windows and does not set the price. The provider may pay Dial Home Help.

What is the lead rule doing on a window page?

Replacement can disturb paint. In pre-1978 housing the EPA requires certified firms for renovations that disturb lead-based paint. Ask whether your job is in that category.

Sources