SAPS4U believe in getting the job done within your budget. Not everyone building a house can afford to pay for solar panels and heat pumps and not everyone buying a house is used to such things. If you really want the house to pass SAP 2012 without solar panels or heat pumps you can still do it.

The main thing to concentrate on is U values. Insulation should be as thick as it can possibly be. 150 mm of Kingspan K3 is good for the ground floor. Wall cavities can use 100 mm of Xtratherm Full Fill Cavity insulation. It helps if the roof is a plane roof. This can be insulated very thickly. If cheap mineral wool insulation is thick enough it’ll be as good as anything else. If you have sloping ceilings on the top floor its difficult to install thick layers of insulation without effecting headroom. It is sometimes possible to have a plane roof over most of the house and a sloping roof where you have rooms in the roof. Consider the windows, rooflights and doors. They should have a low U value and a high G value (solar heating.)

Thermal bridges are the places where a wall meets a window, a floor or a roof. You can prevent heat loss if these are well constructed and you will also make the house more air tight. Accredited Construction Details should always be used and the required air tightness for SAP 2012 is Q = 5. Enhanced Construction Details are good but expensive. There are different schemes but some involve an awful lot of thermal plasterboard on the roof and the walls. Others would require you to use products from the company that produced them and to get the U values, including your windows, exactly right. You can get reasonable results using Accredited Construction Details and thermal lintels on the window heads – cheaper and easier.

Use a high specification gas boiler that is suitable for the house you will put it in. Combi boilers tend to be very efficient in small buildings but poor at sending water long distances. Large hot water tanks are good at sending water long distances. Decide whether a combi is best or whether the house needs a hot water tank. The Alpha Intec 28X is a non-storage combi and the water is heated instantaneously. It has a gas flue heat recovery system so that waste heat from the exhaust can be put into the cold water. Its excellent hot water efficiency makes it good for a small house where its main job will be producing hot water. In a large building a Ravenheat CSI System boiler is good. You can add a gas flue heat recovery unit to it and then add a weather compensator or a delayed start stat (this does the same thing but has the temperature sensor in the house.) A zone control giving separate timing to bedrooms and living rooms should always be used in SAP 2012 in any house, large or small.


SAP 2012 No Solar PV or Heat Pumps
Tagged on: