Best U-Factor and SHGC for Windows in Maryland
Data updated October 12, 2026.
ENERGY STAR Version 7.0 splits Maryland into 2 climate zones: North-Central, Northern. The limits for each are in the table below. Check your address with the ENERGY STAR climate zone finder.
| ENERGY STAR zone | U-factor | SHGC |
|---|---|---|
| North-Central | 0.25 or lower | 0.40 or lower |
| Northern | 0.22 or lower | 0.17 or higher |
Across Maryland, in the GlassBase heating and cooling model, replacing a single-pane window with an ENERGY STAR window saves 505 kWh per window per year. Upgrading a double-pane window saves 195 kWh.
In the Northern zone, the SHGC limit is a minimum, not a maximum. ENERGY STAR also lets a window with a slightly higher U-factor qualify if its SHGC is high enough to collect more winter sun. See window energy ratings in the US for the full table.
What matters most for windows in Maryland
In Maryland, most of the modeled saving comes from heating: 313 kWh of heating load against 192 kWh of cooling load per window per year, for a single-pane to ENERGY STAR upgrade. U-factor measures how fast heat passes through the window. A lower U-factor means less heat lost in winter.
Results vary inside the state; see the city table below.
Modeled savings per window per year across Maryland
One window of 39 × 59 in (1 × 1.5 m), averaged over eight facing directions. Weather: 19 TMY3 weather stations.
| Upgrade | Heating saved, kWh/yr | Cooling saved, kWh/yr | Total, kWh/yr | Natural gas saved, therms/yr gas furnace |
Heat pump + AC, $/yr | Gas furnace + AC, $/yr |
|---|---|---|---|---|---|---|
| Single-pane → double-pane | 254 | 56 | 310 | 10.2 | 20 | 20 |
| Single-pane → ENERGY STAR (each location's zone) | 313 | 192 | 505 | 12.6 | 34 | 34 |
| Double-pane → ENERGY STAR (each location's zone) | 59 | 136 | 195 | 2.4 | 14 | 14 |
Dollar figures use Maryland average prices, not your utility's rate. Electricity $0.1948/kWh: Maryland residential average, 2025. Source: U.S. EIA, Electric Power Monthly, Table 5.6.B, residential sector, year-to-date through December 2025, retrieved 2026-10-06. Natural gas $1.55/therm: Maryland residential average, 2024. Source: U.S. EIA, Natural Gas Prices: price delivered to residential consumers, and heat content of natural gas delivered to consumers, 2024, retrieved 2026-10-06. Heat pump COP 3.2, air conditioner COP 2.5, gas furnace efficiency 85%.
The single-pane and double-pane windows use values from the calculator's reference-window table. In Maryland, each location uses the limits of its own ENERGY STAR zone (North-Central, Northern). kWh here measures heat, not electricity on a bill. Air leakage and the rest of the house are not modeled. Model version tmy3-hourly-iso13790/f4822a26309b, data run October 12, 2026. How the model works.
Cities in Maryland
Modeled savings per window per year in Maryland cities with a GlassBase page.
| City | ENERGY STAR zone | Total, kWh/yr single-pane → ENERGY STAR | Total, kWh/yr double-pane → ENERGY STAR |
|---|---|---|---|
| Baltimore | North-Central | 509 | 199 |
| Silver Spring | North-Central | 497 | 198 |
| Frederick | North-Central | 528 | 193 |
| Gaithersburg | North-Central | 520 | 201 |
| Hagerstown | North-Central | 484 | 167 |
| Germantown | North-Central | 529 | 202 |
| Waldorf | North-Central | 499 | 188 |
| Salisbury | North-Central | 494 | 209 |
| College Park | North-Central | 497 | 198 |
| Beltsville | North-Central | 499 | 188 |
Payback of each upgrade in Maryland
Calculate savings for your ZIP code
Compare states: window energy savings by state.
Frequently asked questions
Which ENERGY STAR climate zone is my home in?
Maryland has 2 zones: North-Central, Northern. ENERGY STAR assigns them by county, and in some places by ZIP code. The ENERGY STAR climate zone finder gives the zone for an address.
How much can new windows save in Maryland?
Across Maryland, for a single-pane to ENERGY STAR upgrade, the GlassBase heating and cooling model saves 505 kWh per window per year. At Maryland's 2025 average prices from the U.S. Energy Information Administration (EIA), the single-pane to ENERGY STAR upgrade is worth about $34 per window per year with a heat pump. Results differ from place to place; use the calculator for your ZIP code.
Is the ENERGY STAR zone the same as the building code climate zone?
No. ENERGY STAR uses four zones of its own, assigned by state and county. Building energy codes use the IECC climate zones, a separate map with its own window requirements. A window can meet one and not the other, so check both if your project needs a permit.