In the current climate, overheating your home is a common issue, especially in the UK, where builders design houses to retain heat. We took a look at the issue.
Key Factors
In modern buildings, there are two basic causes of overheating. The first is climate change. As a result, extreme weather phenomena, such as heat waves, become more frequent. For instance, a heatwave that France experienced in 2003 resulted in 15,000 fatalities. The second factor is the expansion of thermal insulation in contemporary structures. This is both in terms of quantity and effectiveness. Buildings can be especially prone to overheating due to their airtight structure. Manufacturers tend to make windows that to retain the heat of the sun.
Can We Define It?
Although there is no universally accepted definition of what overheating is, most people feel warm around 25°C, hot at 28°C, and put themselves at risk of heat stress at 35°C. But other factors, such as the duration of the exposure and the absence of air movement, have an impact on humans as well.
External Causes
External and internal gains lead to building overheating. Sunlight and soaring outside temperatures are the factors that contribute to external benefits. Through the building’s absorption, solar heat that enters the home through the windows is trapped. Opening a window may not provide comfort. This is because high outside temperatures make it worse. You limit heat losses via the walls and roof. In cities, where nearby buildings reflect heat during the day and release it at night, the issue is often severe. As a byproduct, air conditioning equipment generates heat, which exacerbates the issue.
Overheating Your Home – Internal Causes
A mix of building services, lighting, appliances, and occupants result in internal gains. Lighting and appliances should use the least amount of energy feasible to reduce this. At repose, a typical individual emits 100W of heat energy. In low energy homes, rooms typically only require 300–400W of heating in the middle of winter, thus it is simple to understand how a room could quickly get too warm. In addition, inadequately specified or installed heating systems and mechanical ventilation systems can cause overheating in buildings.
Reduce Overheating
What steps can we take to lessen the impact of overheating? Although the site context—urban or rural—orientation, design, and thermal mass of the building are all crucial factors, I will focus on the role that building services play in reducing overheating in this essay. The three main focuses of passive building service design are minimization of internal service gains, management of shade to exclude sunlight from entering the building, and purging ventilation. In a subsequent blog, active systems like air conditioning will be discussed.
The internal gains can be minimised with good service control. A secondary circulation hot water system’s intelligent control guarantees that the pump only runs when restrooms are occupied. As a result, less energy is released into the structure.
Overheating Your Home – Heating Systems
Additionally important is picking the right heating system. Even in the middle of winter, overheating can become a problem with a heating system that is too sluggish to react or has a large thermal mass.
For instance, a room might be heated at 21°C during the winter using underfloor heating. In order to make up for the heat losses through the walls and ventilation, the floor is heated slightly above ambient temperature. Three more people enter the room as the sun begins to shine, adding more heat sources. It will now be 21 degrees in the room and becoming warmer. The floor will continue to radiate heat for hours until it cools down after the underfloor heating stops. To cool the space, windows will need to be opened.
This issue would not have developed if a heating system that was more responsive had been built. This would improve comfort for those inside and lower operating expenses. Alternative heating systems will probably be less expensive to install.
Overheating Your Home – Shading
The amount of sunshine that enters a building will be lessened through shading. The best way to provide shading is to use shutters or awnings on the outside of a structure. This prevents the energy from entering the building and the light from shining. Although they can be used, blinds and curtains will only reflect a limited amount of the light energy entering the building. Indeed, curtains and blinds keep the heat from entering the centre of the room, keeping it at a more comfortable temperature and preventing bleaching of the furnishings and floor coverings.
Purge Ventilation
By circulating large quantities of air through a building, purge ventilation lowers overheating. The two purging ventilation techniques that can be used are cross ventilation and passive stack. When the outside temperature is lower than the interior temperature, the bottom floor vents or windows, along with a high level window or roof light, are opened as passive stack ventilation. The cooler internal air will enter the low level vents, while the warmer (and less dense) internal air will ascend up and out of the roof light or high up vent.
Cross Ventilation
Cross ventilation is the process of opening windows or vents on either side of a building to create a through draught. Security can be a problem with cross ventilation because windows must be left open, thus we frequently employ bigger DCV (demand control ventilation) vents in their place. These permit safe air volume flows without jeopardising safety. Select windows can incorporate window motors, which is an efficient and reasonably priced option. Automated windows are useful in apartments with only one aspect since they reduce cross ventilation when connected to other vents in the room.
