What is a good ER value for windows?

The ER grade is a single number — the higher the number, the more efficient the window. To achieve ENERGY STAR® certification and qualify for Canada's Greener Homes Grant, a window's ER must be 34 or higher. If a window achieves an ER of 40 or higher, it receives “most efficient” certification.

What is the best ER rating for windows?

ER is an alternative rating, and it includes the solar gain effect of the window. The higher the ER, the more energy efficient the window. Good performing windows and doors have an ER of 29 or higher.

What R-value do I need for windows?

Surace says all windows should perform no lower than R-5, but he believes R-7 should (and will) be the standard. The company, for its part, produces some of the highest-performing products on the market, including fiberglass and vinyl products that range anywhere from R-5.9 to R-11.1.

What is a high R-value for windows?

A high-R-value window has a greater resistance to heat flow and a higher insulating value than one with a low R-value. R-value is the inverse of the U-factor (R = 1/U) and is expressed in units of hr-sq ft-°F/Btu.

Is .30 a good U-factor for windows?

For most energy-efficient windows, the U-factor for the entire window assembly is higher than the U-factor at the center of the glass. The best, high-performance, double-pane windows may have a U-factor of 0.30 or lower, indicating that they are very energy-efficient.

What are ER Ratings - Energy Ratings Explained

Is 1.2 A good U-value for windows?

', according to Part L1A of current Building Regulations a domestic window installation should achieve a U-value no higher than 1.4 W/m²K*. Typical u values for windows that are double glazed record a U-value of between 1.2 W/m²K and 3.7 W/m²K, while triple glazed windows are usually rated below 1 W/m²K.

What is a good U-value for glass?

Building Regulations U Values for Glass

When renovating or extending a home the glazing elements must have a Uw value of 1.6 W/m2K or better. For a new build house you have to look at the energy requirements of the building as a whole but the glazing cannot have a Uw value of worse than 2.00 W/m2K.

What is the R-value of a double glazed window?

R-value measures resistance to heat gain or loss. A typical insulated wall has an R-value anywhere from 12 to 19, while a double-pane window has an R-value of about 2. By using movable insulation within the window frame, the R-value nearly doubles. This will help reduce a home's overall heating and cooling load.

What is the R-value of triple pane windows?

Double-pane windows have an R-value ranging from 3 to 3.8, while triple-paned windows have an R-value of up to 7- 8, making them more effective at blocking heat flow. This means that replacing double-paned units with triple-paned windows reduces heating costs.

What is a good R-value?

Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.

What is a good R-value for windows in Canada?

Double-pane windows provide an R-value ranging from 3 to 3.8. In contrast, triple-paned windows usually offer an R-value of 5, making them more efficient when blocking heat flow. Basically, if you replace the double-paned units with triple-paned ones, it will reduce your heating costs.

What is a good energy efficiency rating?

EPC ratings. Your property will be given an energy-efficiency grade between A and G, with A being the best - ie most energy-efficient - and G being the worst. New-build homes tend to have high EPC ratings, while older homes often have lower ratings of around D or E.

How can I tell if my windows are energy-efficient?

First look for the ENERGY STAR label when buying new windows. Then review ratings on the energy performance label from the National Fenestration Rating Council (NFRC) to find the most efficient windows for your needs.

What is a good energy performance rating?

Energy efficiency within EPCs are graded between A and G – A being the highest level of efficiency and G being the lowest. In most homes, an energy performance certificate rating of D is most common. A good EPC rating will vary depending on your circumstances.

Are Low-E argon windows worth it?

Glass Reduces Utility Bills

Low-E windows reduce infrared light from the outside, but they also prevent heat transfer from the inside. They'll keep your home cooler in the summer and warmer in the winter. You'll be more comfortable and save money on your energy bills in the process.

What windows are most energy-efficient?

Is triple pane worth the money?

Triple pane windows can be up to 50 percent more energy efficient than a single pane window, and up to 20 percent more efficient than a double pane. If you live in an extremely cold climate, double and triple pane windows can have a significant impact on your heating and cooling bills.

What is the U-value of a single glazed window?

The single-glazed window achieves a U-value of 4.8, but it is interesting to note that significant improvements can be made by benign measures such as closing internal shutters, which brings the U-value down to 3.0. Adding secondary glazing can bring it down to 2.9, depending on its design and quality.

Is higher R-value better?

The R-value for insulation is a way to measure how much resistance the insulation has to heat flow. The higher the R-value, the more the resistance and the better the material is at insulating a home. Generally, insulation materials with higher R-values cost more when compared to those with lower R-values.

Is lower U-value better?

U-values can tell you how well an insulated glass unit (IGU) will hold in heated or cooled air. The lower the number, the better the insulating performance. U-values generally range from 0.1 (very little heat loss) to 1.0 (high heat loss).

Is 1.6 U-value good?

Low U-Values indicate that a window will perform well in maintaining the indoor temperature of a customer's home. Recently building regulations have changed, meaning that new windows must have a u-Value below 1.6 W/m2k.

What is the U-value of triple glazing?

Triple glazing is generally supplied with an overall thickness of 28 – 44mm. A 28mm unit with 1 low-e coating will achieve a centre pane u-value of 1.3, in this configuration, triple glazing would not be more energy efficient than a double glazed unit.

What does energy rating E mean?

EPC rating C = 69-80 SAP points. EPC rating D = 55-68 SAP points. EPC rating E = 39-54 SAP points. EPC rating F = 21-38 SAP points. EPC rating G = 1-20 SAP points (least efficient)