What is the best solution for heat loss through windows in existing buildings?

There are the commercially-available plastic window films (similar to plastic wrap) that can be attached to the window trim using double-sided tape and then stretched tight using a heat gun. It acts similarly to another pane of glass by requiring additional convection to take place for heat to pass through the window. These are a pretty simple, seasonal, home improvement solution. I'm not sure what else is out there.

Conventional folks use curtains but I put a plastic panel against the wall sealing the window area. It saves significant heat because there is condensation all over the glass. Most heat is lost through windows. Two double glass windows in series is a solution if you must see out.

Air is one of the best insultating agents. You have to contain it between multiple glasses, or multiple plastic panels (i suggest polycarbonate). If these are transparente sunlight can enter in the rooms but not go out dissipating its energy on the walls and giving heat and so temperature increase

In the industry, much work is done to reduce the heat loss from windows. I do not recall all of the commercial-level alternatives, but one solution is to put some sort of thin metal sheet on top of the surface of one glass, which still lets most of visible light through but blocks some thermal radiation. Some special glass is also used, but I don't know about their properties. These topics are covered from time to time in general home builders' magazines, but I'd propose you go through some window manufacturers' websites and advertisement material to get a comprehension of the current commercial solutions.

HI everyone,

For reducing heat loss (or preventing heat coming in) through your windows, there are multiple systems available on the market. The simplest and cheapest are the heat reflective sheet. These are applied to the window panes by self adhesive (the sheets already have their own glue on one side). But you have to choose carefully, as some sheets are for cold climate, and other are for hot places. If you choose wrongly, you might have the one that will shrink in service. Those sheets that are used on automotive glass (to blacken, or reduce visibility into the car) have multi-level of shading. Those that are less dark are suitable for the house windows.

Another system, albeit more expensive is the double glazing system. It is basically windows with double glass panes. This traps air in between the two panels, thus increasing the insulation index, but still pass enough light through.

Happy trying folks.

Wan Zaidi

Hi Sahar, you are talking about "heat loss", yes certain films will help but only very very marginally, as glass is opaque to infra-red (heat) anyway. If you are trying to improve the thermal efficiency Luca & Charles are absolutely right trap a layer of air, 5-20mm is good, more would increase convection within the cavity, therefore more heat loss.

I have successfully specified various secondary blinds to improve the performance, such as http://www.insu.co.uk/window-enhancement/insulating-blinds/ (virtually invisible). The problem being storage during the good weather, damage to panels and general need for removeal and replacement.

In UK I also specified Duette shades (expensive and difficult to obtain), but very good tracked fixing on the sides of the windows and can be adjusted within the opening to suit when ventilation is required, variety of colours and textures was also very useful especially to the decor conscious ladies of the house.

Thermal imaging photos showed the improved performance against the non-insulated windows.

Mr Patauner,

I appreciate your answer, I think we also go for concave shape window to reduce the heat loss i.e as follows:

1. Incident ray temparuture decreases as it comes out of concave as refracted rays

2.The cost of the window may increase

3. Smart Window has to designed i.e combination of Concave-Convex window.

4. Plese see other related answer in the attachments

Dr Dharmasa

IEEE Br. Counsellor

Oman

Dear,

You can try this also I.e water filled window.It is an new concept.

Dr Dharmasa,IEEE MD OFFICER OMAN

ADDITIONAL POINTS

How much temp you wants to reduce.

how much you can money you can spend per sq meter of window

it good under gulf condition

Dear colleagues,

I think perhaps the target should be not necessarily what is the best technology to minimize electricity bills? but, instead:  what solution will minimize the overall cost on a life cycle analysis of our system?

On that regard, the proposed solution must account for initial cost + O&M cost-saving of the proposed efficient technology and verify that monthly or annual savings can pay investment back in short term with attractive IRR and B-C returns.

My suggestion is to assess the multiple new technologies proposed by colleagues and available in the market with proven better efficiency than current technology in place. Then, perform a Life Cycle Cost analysis and determine if the more efficient technology pays its cost back and with attractive indicators for the investor under local legislation (check if there are incentives for example).

One tool that I recommend is RETScreen. It´s free (retscreen.net) and has a thorough worksheet section for building envelop and multiple case studies to guide you.

Best of luck and hope it helps!

Luis

Aerogel

Dear Prof.

Using Energy+ and design builder software can be helpful.

Best regards,

use buble wrap to avoid heat leakage