ENERGY STAR Version 7.0 for windows took effect on October 23, 2023. In the Northern zone, which includes all of Minnesota, a certified window must have a U-factor of 0.22 or lower and a solar heat gain coefficient of at least 0.17. Sliding glass doors must reach 0.26 or lower. A standard double-pane, Low-E, argon window from the previous version usually does not qualify anymore.
The label on the window did not change much, but the bar behind it did. This post covers what moved, how a window reaches the new numbers, what the separate Most Efficient designation means, and how to use all of it when you are comparing quotes. For the basics of reading a U-factor and SHGC, start with our ratings explainer at jmbbuildersmn.com/blog/window-energy-ratings-explained.
What changed from Version 6.0 to Version 7.0?
The EPA lowered the allowed U-factor in every climate zone, tightened the SHGC limits in the two southern zones, and added something the Northern zone never had before: a minimum SHGC. Certification bodies stopped accepting new products under Version 6.0 in April 2023, and after October 23, 2023 every window, door and skylight manufactured had to meet 7.0 to be labeled.
For Minnesota buyers the practical effect is simple. Under the old version a well-built double-pane window with Low-E and argon qualified comfortably. Under 7.0 many of those same windows fall just short and lost the label, even though the window itself did not change. Manufacturers responded by adding triple-pane options, room-side Low-E coatings and better spacers to their Northern packages.
That is why you may see the same product line offered both with and without the ENERGY STAR label depending on the glass package chosen. The label follows the glass, not the brand.
The two stickers on a new window are easy to mix up. The NFRC label lists the measured ratings: U-factor, SHGC, visible transmittance and sometimes air leakage and condensation resistance. The ENERGY STAR label sits beside it with a small map showing the zones where that exact glass package qualifies. A window can carry an NFRC label and no ENERGY STAR label at all, and a window can be ENERGY STAR for the Southern zone and not for Minnesota. Look at the map, not just the logo.
What are the Northern zone numbers under Version 7.0?
ENERGY STAR divides the country into four climate zones. Minnesota is entirely in the Northern zone, the heating-dominated one. The criteria below are the ones a window sold here has to meet to carry the label.
| Product | U-factor | SHGC |
|---|---|---|
| Windows (prescriptive path) | 0.22 or lower | 0.17 or higher |
| Windows (equivalent energy performance) | Slightly higher U-factor allowed | Paired with a higher minimum SHGC set by the criteria table |
| Sliding glass (patio) doors | 0.26 or lower | No maximum in the Northern zone |
Why did the Northern zone get a minimum SHGC?
SHGC, the solar heat gain coefficient, is the share of the sun's heat that gets through the glass. In Texas the program wants it low. In Minnesota, where the heating season runs from October into April, sun coming through a south window in January is heat you do not have to buy. Version 7.0 is the first time the Northern criteria say so directly: a window cannot qualify by blocking the sun so hard that it gives up that gain.
The equivalent-energy path works the same way. A window with a U-factor a little above 0.22 can still qualify if it has a high enough SHGC, because the extra sun offsets the extra heat loss over a heating season. ENERGY STAR has offered this trade-off in the Northern zone for years; 7.0 kept it.
For a homeowner this means the glass coating matters as much as the pane count. A high-solar-gain Low-E on the south side and a lower-gain one on the west is a reasonable way to build a Minnesota order, and both can carry the label. Our guide to choosing Low-E by orientation is at jmbbuildersmn.com/blog/which-low-e-coating-minnesota-north-vs-south-windows.
How does a window actually reach a 0.22 U-factor?
The NFRC U-factor is a whole-unit number: glass, spacer, frame and sash together, on a standard test size. Center-of-glass numbers that a glass maker publishes are always better than the whole unit, because the frame and the edge of the glass drag the average down. To get the whole window to 0.22 or lower, manufacturers pull on four levers:
- Triple-pane glass. Two gas spaces instead of one is the most direct route and the most common Northern package now. Triple-pane is heavier and needs a frame built for it. Our double vs. triple comparison is at jmbbuildersmn.com/blog/double-pane-vs-triple-pane-windows-minnesota.
- A room-side Low-E coating on surface 4 (Cardinal's LoE-i89, sold by window brands under names like Andersen HeatLock and Marvin ERS). It reflects room heat back inside and can get a double-pane unit close to or under the line.
- Argon or krypton fill and a warm-edge spacer. The gas lowers conduction in the gap; the spacer keeps the glass edge from bleeding heat into the frame. See jmbbuildersmn.com/blog/argon-vs-krypton-gas-fill-windows and jmbbuildersmn.com/blog/warm-edge-spacers-explained.
- The frame. Foam-filled vinyl and fiberglass frames, multi-chamber extrusions and wider frames all lower the unit U-factor. A thin aluminum frame will not get there no matter what the glass does.
What is ENERGY STAR Most Efficient?
Most Efficient is a recognition tier above ordinary certification. For windows the bar is a U-factor of 0.20 or lower, which in practice means triple glazing. The EPA publishes the qualifying product lines each year, and the list is shorter than the full certified list.
The designation has mattered for incentives. Federal tax credit rules for windows were tied to Most Efficient rather than to plain ENERGY STAR certification, and utility rebate programs sometimes use it as their cutoff. Incentive rules change more often than window specifications do, so before you order, check the current federal rules and your utility's program rather than a salesperson's summary from last year.
For a Minnesota house, Most Efficient is worth asking about when you are already buying triple-pane. It is not worth forcing onto a budget double-pane order; you would be paying for a label, not comfort.
One practical note: Most Efficient is recognized per product line and glass package, and the list is updated yearly, so a window that qualified last year may not appear on this year's list even though nothing about it changed. If a rebate depends on it, ask the manufacturer for the current recognition letter for the exact series and glass you are ordering, and keep it with the invoice.
What does Version 7.0 mean for a Twin Cities window order?
It changes how you read a quote. Under 6.0 the label was almost a given; under 7.0 it separates glass packages. A few things to ask for in writing:
- 1The NFRC ratings for the exact glass package quoted, per window style, not the best number in the brochure. A casement and a double-hung in the same series with the same glass have different U-factors.
- 2Whether the package is ENERGY STAR certified for the Northern zone under Version 7.0. If the answer is the brand name, ask again.
- 3How the window reaches the number: triple-pane, surface-4 coating, or both. This tells you about weight, glass color and inside-surface temperature, not just the rating.
- 4The SHGC, and whether it varies by elevation. A single low-gain coating on every window is easy to order and not always the best for a heating climate.
- 5The air-leakage rating on the NFRC label. It is optional for manufacturers to list and tells you how tight the sash is in the frame.
Does the label matter if the install is poor?
The label rates the window. The house gets what the installer leaves behind. A 0.22 triple-pane set into an open rough-opening gap with fiberglass stuffed around it leaks air around the frame and the room feels no better than it did. The interior air seal, the sill pan and the flashing are not on any label, and they are where most callbacks come from.
When you compare bids, weigh the install description as heavily as the glass. Low-expansion foam or backer rod at the interior edge, a sill pan, taped jambs and head, and casing reset over a sealed gap. Our post on insulating around the window covers that side: jmbbuildersmn.com/blog/how-to-insulate-around-windows-minnesota.
One more caution: ENERGY STAR is a threshold, not a ranking. Two certified windows can differ meaningfully in U-factor, condensation resistance and air leakage. Once both bids clear the label, compare the numbers underneath it.
What JMB Builders does
JMB Builders is a licensed Minnesota residential building contractor (BC809005) based in Zimmerman, working across the Twin Cities metro. We install every brand and are a dealer for none, so we read the NFRC label with you rather than sell you one. One crew measures, installs and trims. Paid by check or direct deposit. Call 763-204-2099 or send photos through the site.
- Labor-only installation of ENERGY STAR windows you bought at a store or online — jmbbuildersmn.com/services/labor-only
- Which windows to buy for a labor-only install, including how to read the glass package on the order — jmbbuildersmn.com/services/labor-only/which-window-brand-to-buy-for-labor-only-install
- Insert and full-frame replacement windows and doors, measured and ordered by us — jmbbuildersmn.com/services/full-service
- Andersen 100 and 400 Series installation, labor only — jmbbuildersmn.com/services/labor-only/andersen-100-400-window-install-labor-only
- Send three photos, written quote within one business day.
Frequently asked questions
What U-factor do windows need to be ENERGY STAR in Minnesota?
Under Version 7.0, a window sold in the Northern zone, which covers all of Minnesota, needs a U-factor of 0.22 or lower and an SHGC of 0.17 or higher. Sliding glass doors need a U-factor of 0.26 or lower. ENERGY STAR also allows an equivalent-energy path where a slightly higher U-factor qualifies when paired with a higher SHGC.
When did ENERGY STAR Version 7.0 take effect for windows?
October 23, 2023. Windows, doors and skylights manufactured after that date must meet Version 7.0 to carry the ENERGY STAR label. Certification of new products under the previous version stopped six months earlier, in April 2023.
Are double-pane windows still ENERGY STAR rated in Minnesota?
Some are, but most standard double-pane packages do not reach 0.22. The double-pane units that qualify in the Northern zone usually add a room-side Low-E coating on the inside surface of the glass, argon fill, a warm-edge spacer and a well-insulated frame. Triple-pane is the more common route to the label now.
What is the difference between ENERGY STAR and ENERGY STAR Most Efficient for windows?
ENERGY STAR certification is the base threshold, 0.22 U-factor in the Northern zone. Most Efficient is a higher recognition tier at a U-factor of 0.20 or lower, which in practice means triple-pane glass. Federal window tax credits and some utility rebates have been tied to Most Efficient rather than to plain certification, so check the current rules before you order.
Why does ENERGY STAR require a minimum SHGC in the Northern zone?
Because in a heating climate, winter sun through the glass offsets heating. Version 7.0 added a Northern minimum SHGC of 0.17 so that a window cannot qualify by blocking so much solar heat that it loses that benefit. It is the first version of the standard to set a floor on solar gain in the north.
Does an ENERGY STAR window guarantee a warmer room?
No. The label rates the window unit as tested. The comfort you feel depends just as much on the gap around the frame being sealed with low-expansion foam or backer rod, on the sill pan and flashing, and on the sash weatherstripping. A certified window installed with an open frame gap still leaks.
