At What Level Of Airtightness Is Mechanical Ventilation And Heat Recovery System Worthwhile

Although Mechanical ventilation and heat recovery system can be installed in any building, there is a rule of thumb that its use is now not justified unless the air permeability of the thermal envelope is at or beneath 3 air changes per hour when examined at 50 Pascal (equivalent about to three m3/m2.h @ 50 Pa for average dwellings). If this degree of airtightness is now not performed then the herbal respiration of the constructing is such that alternative techniques to air flow are greater appropriate.

If there is no temperature distinction between interior and outside then there is no energy to be recovered. When you have a substantial temperature difference between inner and outdoor then the thermal stacking effect (or chimney, warm air rising effect) becomes the driver that will cause your building to ventilate itself through the leakiness of the envelope. If it is windy then you will have wind as the driver ventilating your house thru the envelope leakiness. By the use of intermittent extract at point of need, e.g. shower, kitchen, you will surely reverse some of the leakiness.

If your building has terrible insulation/thermal bridging and or other damp ingress due to for instance lack of acceptable damp proofing, then it can be tempting to seem for technological solutions. In such a state of affairs you will have troubles with condensation and likely mildew the place the condensation is forming. Yes warmth recovery ventilation can help limit these symptoms; however, our advice would be to kind out the problem not cure the symptom.