Im looking at buying energy efficient windows for my home. I hear they can considerably reduce heating loss in winter while keeping the place cool in Summer. Does anyone know rounghly how much they cost and are they worth the investment?
Looking here - https://priceexperts.co.uk/window-prices/energy-efficient/ - there’s a rough estimate. Does anyone have any experience cost versus benefit?
Windows are a long term investment and do not expect energy savings alone to justify replacing them. In most homes, your limited dollars for investing in energy saving measures would not go to windows unless you had addressed other systems first -- air sealing, insulation, reducing plug load, etc. However if you are planning to replace windows anyway for aesthetic reasons or resale, definitely do your homework so you buy the more efficient models. You may be in a situation where replacing your storm windows would make sense. Here is a good basic place to start looking at options. https://www.energy.gov/energysaver/energy-saver
If you're looking for energy gains and your windows are old, here's my general approach:
1) if they are old metal-frame windows, then replacing is probably a good idea as the metal brings a lot of outside temperature in (thermal bridging). Otherwise (as Barbara said) it's replacing mostly makes sense if you're looking for other purposes.
2) But there's lots you can do to improve the efficiency of your existing windows. Start by making sure you don't have drafts coming in around the window - and air seal if you do. If it's real bad, you may want to remove trim and use (window-specific) spray-foam around the window. Second, look at ways to create an additional, well-sealed barrier. Typically this means some kind of storm window to create another barrier against the cold. Lots of different approaches can be done here with lots of different impacts, and can be done on the exterior or interior, ranging from $10 / window to $200 / window. Just make sure you can live with the aesthetics and that the seal around it is good so it creates another air barrier and creates an insulating layer with the air between the window and the storm.
Caveat #1: All of this said, lots of specific factors can create different recommendations depending on your weather, goals, local climate, existing windows, etc.
Caveat #2: This is my general approach for just generally improving efficiency. If you're looking for a deep retrofit (ala Zero Energy or Zero Energy Ready), then it may be a different story.
Let's talk incremental cost. You could buy double pane windows. Standard size about $10 - 15 per SF, Custom $25 - 30. EnergyStar Standard size $25 to 30, EnergyStar Custom $35 to 40.
Ultra Premium (Triple pane, fiberglass frame, $40 to $60 per SF. I am a fan of minimum effective dose methodology. All of these are more expensive and less effective than R13 wall.
So what is a window. Source of light, views, ventilation. What do good windows improve? Less cooling through tinting and thermal conductivity. Less heating by infiltration reduction and thermal conductivity. Less noise transmission. Possibly better operation, intrusion resistance, etc.
Don't look for the energy savings to pay for the window project. Look for the best energy per dollar benefit. Typically once you pass EnergyStar, the costs climb faster than the savings. I have a sermon that I give on super insulating which also translates to ultra efficient windows. This improvement lowers the balance point of the building (temperature where the building changes from heating to cooling). This causes the building to require more cooling. The good news is the additional cooling is the cheapest cooling, like when it is 55 deg outside.
For both new and existing homes, Energy efficient windows are an important consideration
Heat gain and heat loss through windows are responsible for residential heating and cooling energy use.
These windows are totally worthy to invest.
Consult energy efficient consultant, they will give better advice and help in installment.