Frequently Asked Questions (FAQs)

14.   Whole building ventilation - Healthy House systems explained

What is it?

• It is a ventilation machine that is specifically made for new buildings or 'renovated'* old buildings.
• It filters the outside air as it comes in and removes old (or polluted) air from inside the building.
• The INCOMING and the OUTGOING air come in and out at the same rate (so its called a balanced system).

Its purpose?

• It provides the whole building with a continuous (and controlled) fresh airflow, no matter what is happening in the building or outside.
• When we say 'controlled' it means we have a say in how much outside air is brought in and how filtered that air is.

What else does it do and why is it now so important?

• Depending on the season we may have a 'heater' or a 'cooler' on inside the building (lets call this 'heat' or 'cool' energy). It costs money to heat or cool our homes.
• The ventilation machine brings new air in and removes the stale old air, it does not heat or cool the air.
• The air in your home has been either been heated or cooled by a heater or air conditioner. As the air leaves the building the ventilator catches the energy (hot or cool) and passes it to the new air stream coming in. This is an energy (heat or cool) transfer.
• The air streams never mix but pass so close to each other that the energy (heat or cool) flows to the new air.

So, that means that we don't lose that energy to the outside. We have paid to heat or cool our inside air and by recovering that and reusing it, we become very energy efficient and also save money.

Two types with different names for different jobs.

• So not to waste that 'heat' the ventilator passes that 'heat' (or energy) to the new air being brought in.
• This saves an enormous amount of energy (heat) being lost outside as well as new energy being used to reheat the new air coming in. HRVs can also remove excess moisture from your home.

A variation of an HRV is an ERV (or Energy Recovery Ventilator).

• Like the HRV, the ERV allows you to 'recover' heat or cool but also to monitor and control moisture in the air to suit the climate. They are usually used in hot humid or hot dry climates. The moisture comes from what we do in the house. We breathe, our bodies give off moisture, we cook and shower etc. This moisture affects your health and the health of the building.
• The created moisture is absorbed into our furnishings and then released. When released the 'moisture filled' air is full of pollutants from the glues and chemicals used in the construction process. These pollutants cause health problems- asthma and allergies. Mould and spores love moisture too. Building structures are also badly affected by moisture.

Why do buildings, people and the planet need it NOW?

• It's all about the air quality in the building. We try to reduce heating and cooling costs by building structures that are well insulated and don't leak air.
• These 'tight' buildings don't allow 'moisture filled' air to escape thereby creating potential health problems
• CO2 is one of the offending gases warming the planet. If we reduce our energy requirements for heating and cooling then we help reduce C02 levels
• Reducing air pollution is crucial.

*a 'renovated' building will have all existing gaps and cracks sealed to reduce air leakage.