Solar gain limit exceeded
Priority for Completion: High for buildings with cooling systems or mechanical ventilation
This is one of the most misunderstood recommendations that appears on non-domestic Energy Performance Certificates. It is often easily fixed and can save significant amounts of energy in buildings with cooling, air-conditioning or mechanical ventventilation systems. In other buildings it may actually help reduce the energy used for heating and associated costs but may also reduce the comfort of building users.
What is solar gain?
In simple terms, solar gain is the heat a building gains from the Sun shining through the windows. Just as a greenhouse warms up during the day, glazing allows energy from the Sun to enter the building where some of it is trapped. This energy is converted to heat within the building environment.
NB: We do not endorse this particular product, manufacturer or installer.
Why is solar gain a problem?
Having solar gain within a building is not always a problem. In fact, it can be beneficial as it can reduce your heating demand. However, if you have too much solar gain then modern buildings can get very hot, even to the point where they are not just uncomfortable but can become dangerously hot. The key is getting the right balance.
As you can imagine, adding a cooling system into the mix is likely to result in awful energy efficiency. The more solar gain their is, the harder the cooling system has to work to keep the building at the preferred temperature. In fact, we often find that excessive solar gain is one of the most common causes for a building not performing with the energy efficiency expected.
How do you reduce solar gain?
The simple answer is that you reduce the amount of solar energy entering the building. You can also improve ventilation to remove any excess heat (e.g. opening windows in the summer).
There are lots of possible ways of achieving this. We recommend talking to your EPC assessor to establish which may be the best options for you. You may also wish to commission additional modelling work or even full thermal comfort modelling to solve these issues depending on the seriousness of the problem and the nature of the building.
Some possible solutions include:
- Applying window coatings to change the amount of solar energy trapped in the building.
- Installing blinds.
- Changing the size or type of glazing.
- Installing brise soleil or other external shading.
- Changing arrangements for natural ventilation.
Other considerations
Please discuss this recommendation with your energy assessor. Depending upon your building this may only be an issue in some areas or throughout the building. You will need your accredited energy assessor to look carefully at the data outputs of the EPC calculations to find out more and advise you as to which areas are causing the problem. If you are constructing a new building and your SBEM calculations for Part L Compliance contain this warning it should be addressed as early as possible in the design process. Fixing this to achieve compliance after construction can be very expensive!
NB: In some buildings this recommendation is activated due to modelling methodology and the need to separate the building into zones. Again, discussing this with your energy assessor will allow you to explore the true cause of this problem.
Solar gain limit exceeded
Priority for Completion: High for buildings with cooling systems or mechanical ventilation
This is one of the most misunderstood recommendations that appears on non-domestic Energy Performance Certificates. It is often easily fixed and can save significant amounts of energy in buildings with cooling, air-conditioning or mechanical ventventilation systems. In other buildings it may actually help reduce the energy used for heating and associated costs but may also reduce the comfort of building users.
What is solar gain?
In simple terms, solar gain is the heat a building gains from the Sun shining through the windows. Just as a greenhouse warms up during the day, glazing allows energy from the Sun to enter the building where some of it is trapped. This energy is converted to heat within the building environment.
NB: We do not endorse this particular product, manufacturer or installer.
Why is solar gain a problem?
Having solar gain within a building is not always a problem. In fact, it can be beneficial as it can reduce your heating demand. However, if you have too much solar gain then modern buildings can get very hot, even to the point where they are not just uncomfortable but can become dangerously hot. The key is getting the right balance.
As you can imagine, adding a cooling system into the mix is likely to result in awful energy efficiency. The more solar gain their is, the harder the cooling system has to work to keep the building at the preferred temperature. In fact, we often find that excessive solar gain is one of the most common causes for a building not performing with the energy efficiency expected.
How do you reduce solar gain?
The simple answer is that you reduce the amount of solar energy entering the building. You can also improve ventilation to remove any excess heat (e.g. opening windows in the summer).
There are lots of possible ways of achieving this. We recommend talking to your EPC assessor to establish which may be the best options for you. You may also wish to commission additional modelling work or even full thermal comfort modelling to solve these issues depending on the seriousness of the problem and the nature of the building.
Some possible solutions include:
- Applying window coatings to change the amount of solar energy trapped in the building.
- Installing blinds.
- Changing the size or type of glazing.
- Installing brise soleil or other external shading.
- Changing arrangements for natural ventilation.
Other considerations
Please discuss this recommendation with your energy assessor. Depending upon your building this may only be an issue in some areas or throughout the building. You will need your accredited energy assessor to look carefully at the data outputs of the EPC calculations to find out more and advise you as to which areas are causing the problem. If you are constructing a new building and your SBEM calculations for Part L Compliance contain this warning it should be addressed as early as possible in the design process. Fixing this to achieve compliance after construction can be very expensive!
NB: In some buildings this recommendation is activated due to modelling methodology and the need to separate the building into zones. Again, discussing this with your energy assessor will allow you to explore the true cause of this problem.