Self Building: Airtight Design Explained (2/2)

A guide to achieving a fully airtight design when constructing your home. Part 2/2.


Continued from Part One 

Airtight Design: Heating the House

One of the major benefits of an airtight design is that the house will need much less heating as it is capable of holding onto the heat generated by its occupants’ day-to-day activities. However, anybody hoping to incorporate traditional open fires will be sorely disappointed as these old designs create far too much air leakage to be included in an airtight house. A popular option is to use a wood burning stove with a special attachment which allows you to draw air from the outside. However, these are still not properly room sealed and opening the door to re-fuel means upsetting the airflow balance and releasing smoke into the room. It is not a bad idea to use a wood burning stove as an accompaniment to underfloor heating on only the coldest of days, and as airtight homes rely on whole-house ventilation regardless, introducing heat recovery to a mechanical system designed to control air changes is quite a popular option.Self Building Airtight Design Explained 2 500x305 Self Building: Airtight Design Explained (2/2)

Mechanical Ventilation

Ventilation is an absolute necessity in any airtight design house, and mechanical ventilation is perfect for the job.

How does it Work?

MVHR works by continuously extracting polluted air from within the airtight design building. All stale air is passed through a heat exchanger, which then works to pre-heat the incoming fresh air from the outside. The environment is this way kept fresher, warmer, and much more comfortable.

What are its Main Benefits?

When dealing with an airtight design house, the airtight properties create a rise in the internal humidity of the home. This can lead to an increase in the damage caused through condensation to both the property itself and the health of its occupants. MVHR is perfect for providing a much greater quality of clean, healthy, fresh air. Additionally, mechanical ventilation will impact upon your energy bills by recovering up to 95% of what would otherwise be wasted heat and therefore reducing the overall heating requirement. This kind of system also means that no window trickle ventilation is necessary, therefore avoiding noise ingress.

How much will it Cost?

You can typically expect such a system to set you back by around £2,000-£5,000, depending upon various factors such as the size of the property.

How is it Installed?

In order to supply each room, a certain amount of ducting will be necessary, but the unit itself is fitted to the wall using brackets. The condense drain is linked to the home’s waste waster system, and the unit is connected to the electrical supply.

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