Overheating of Homes

Overheating of Homes

Overheating of Homes…a sticky situation

The use of large amounts of glass when extending your home is something that almost all
of our customers are desperate to have, and understandably so!


Any house looks luxurious with bespoke bi-fold doors spanning up to 6 metres, or with sliders you get unobstructed panes up to 3 metres for a single pane, the perfect addition to your new dream home. The more glass in your extension you have, the more light will flood in, and happier you and your family will be in your new extension right? Well yes, but there are also some other considerations to bear in mind when deciding that you simply must have an entire wall as glass,
or every window is to be from the floor to the ceiling. A big consideration when designing buildings is that buildings ability to maintain a steady internal temperature throughout the year in this, lets be honest, fairly changeable climate we have to deal with on the fair isle.

Heat in… Heat out!

Glass just isn’t as good as an insulated wall for keeping the heat in, and is absolutely terrible at keeping the heat out in the summer, in fact, it does the opposite! I am sure most of us have walked into a conservatory that has been left to heat up on summer day? When you walk in, the heat hits you like walking into a furnace! Similarly that same conservatory is a no go area in winter when it is just impossible to heat up without seeing a marked increase in Januarys gas bill.

Focus on insulation

Keeping homes cool in the summer is not the focus of the building regulations, they are focusing on insulation and keeping the homes warm in the winter, but with global warming and the subsequent warmer summers, homes being built closer together (thank you very much the planning department), poor temperature controls and ore airtight buildings overheating can be as big a problem!

By definition a building suffers from overheating when the temperature becomes uncomfortable for occupants within a building. Increased humidity can also exacerbate the issue. It therefore must be a consideration when specifying large pieces of glass in any extension, or the orientation of that glass when designing new build housing.

Internal, rear extension, Gosforth

Tricks for blocking the sun

In the UK the Zenith of the sun moves between 62 degrees in summer and 12 degrees in winter, meaning that specially designed shading like larger soffits, or brise soleil might be used to keep the sunshine out during the summer, but let it in during the winter. Another clever trick is to use deciduous trees positioned to block the sun in the summer period but will let light through in winter. Internal blinds can also help, with different glazing also an option to block out the worst of the sun’s rays. It is not just windows that let the heat in. The heat from the sun is defined as radiant heat and when it strikes a solid object it is absorbed and reemitted at a different frequency, as conductive or convective heat. Designers really therefore need to look at the types of wall and roof construction as much of this is only designed to stop the transfer of conductive or convective heat and allows the radiant heat to pass right through into the home. The use of multiple layers of different insulations, air gaps and ventilation
should be considered at the design stage.

Thermal Mass

With the growth of lightweight building systems like timber frame, SIPS panels and pre-insulated shuttered formwork the heat that enters the building quickly heats up only the air without any large amounts of mass (in this instance called thermal mass) to absorb the heat during period of high temperature, and then release that heat during the cooler evenings and night time. It takes around 4 times more energy to heat up a solid that to heat the air, and so including some thermal mass in the building (a concrete floor, granite work tops, masonry chimney breast or even just some denser plasterboard) the tops can be knocked off the peaks during the summer months.

If the property does get too warm, the best way to cool it is through cross ventilation with cooler air. One window is not enough as the air needs to pass from one opening through anther, this is easily achieved on a detached property, but often it is important to think about how to ‘bring in the breeze’ especially on terrace or semidetached property like we have here in the North East. All considerations we take into account for our clients, to make sure they get the dream home that they deserve, on budget and on time.