FAQ – Government Regulations

Below you will find answers to questions we are frequently asked regarding timber sash windows, hinged window and doors. If you have your own questions that are not answered here, please feel free to contact us either by e-mail or by telephone on 0800 783 4053.

What are the current regulations regarding replacing windows/doors?

If you replace your windows and doors, they must comply with a given minimum standard of insulation. This is part of the U.K. Government’s obligation to the E.U. agreement on reducing greenhouse gasses.

What is a “U” value?

U-value is measured by the rate of heat loss from the warm inside of the house through the window/door to the outside, if it’s colder there.

The lower the U-value, the smaller the loss of heat, i.e. better energy management.

What is a “W.E.R”?

This means Window Efficiency Rating. It is mandatory for windows where the total existing frame is to be replaced.

Are these regulations enforceable?

Yes, very much so. There are heavy fines for installers who do not comply, and you will be made to change your windows AGAIN.

How is the system policed?

Total replacements must be registered with the Local Authority. The installation company can either do this themselves, or join an industry organisation, for example FENSA which does this for them.

Acoustic glass may be used on the outside of your double glazed unit.

How does FENSA know what’s going on at my house?

The installer must inform FENSA, who then make random checks from a list of jobs supplied by the installer, to monitor the standard of insulation.

Is this system effective?

Well, self-assessment can be open to abuse. So we suggest you inform the installer that you will check yourselves with the Local Authority after the job is finished to make sure it is properly registered and approved.

Ask the installer for documentation that confirms that Building Regulations are being adhered to.

What happens if I just ignore it all?

Possibly nothing, or more likely a high cost to you, enforced by the law. Whatever happens you will have problems if you want to sell your house, because the solicitors will want evidence of compliance and registration. This started in April, 2002.

What does Original Box Sash Windows Company do?

  1. We are members of FENSA.
  2. Your full replacement work, whether sash windows, hinged casements or glazed doors, will be registered with the Local Authority.
  3. In the likely event that FENSA will never get round to testing your windows/doors, we have had independent testing carried out at the National Physical Laboratory to confirm your windows/doors from us comply with the regulations.
  4. We will issue you with a FENSA certificate and a National Physical Laboratory Certificate. In our opinion, one without the other is not worth much.

What’s the practical benefits to me?

Peace of mind.

Windows/doors that are guaranteed to keep you comfortable, warm, and minimise your fuel bills.

No complications if you sell your house.

Does all this cost any more?

Costs always end up being paid by the customer, but these ones are minimal. However, the cost to you of non compliance will be hundreds of times more, sooner or later when it comes to light.