Home Ventilation Systems – New Zealand Situation

Home Ventilation and the New Zealand Situation
All homes in New Zealand need controlled ventilation, gone are the days – for many reasons – that we can open windows to leave it fresh, aired, pollution, dust and pollen free, without introducing both the cold air and wind blown moisture and still keep them (our homes) secure while we are at home or not, home ventilation systems will give you the fresh air supply that is often drier and sometimes warmer than opening the doors or windows, making your home easier to heat, secure, healthy and condensation free.

Just to repeat a little here (sorry).
The NZ homes built many years ago with T&G flooring, sarked or scrim walls and wooden joinery had plenty of ‘Fresh Air’ flowing through the home, they effectivley had home ventilation systems built in, but the house could have been far warmer. Generally someone was at home to open and close windows and keep the wood fire or coal range going, covering both the ventilation and heating of the home, even though it was not perfect and the homes were cold they were healthier.

Also we did not have the pollution along with the number of people susceptible to either pollens and allergies or asthma attacks, we didn’t get mould growth on our windows and generally the homes were not damp.

Many things have changed over the years, we work longer hours, often both partners work and no one is home for possibly 10 hours of the day, our homes are built far more air tight and we are insulating them better. Along the way we have stopped ventilating our homes like we used to, either to make them more secure or to ‘keep the heat in’ mmmm some interesting things have changed, oh and we also have far more pollution in various forms in many parts of the country, along with a large number people suffering from asthma.

In an extreme I’ve seen people who are effectively at home for 24 hours a day – they work at home and use heat pumps to heat and cool the home, they do not want to open the double glazed windows as they will ‘loose heat’ and believe that the heat pump will give them fresh air, heat pumps – in general – DO NOT give a fresh air supply, they do not replace ventilation systems. A couple of families could not work out why they always felt dozy, (caused by a lack of fresh air) and when any of them got a cold or flu they just could not get rid of it for weeks and often the whole family came down with the symptoms at the same time.

In these New Zealand homes Positive Pressure Home Ventilation Systems really do fix many if not all of these problems, reduced the maintenance on the house and increased the value of these homes.

It is generally known that both New Zealand Homes and New Zealand’s weather are damper than the UK (when the UK and Europe gets cold it is quite dry). The US (in most states) is also far drier than here in New Zealand. Yes the moisture is still developed by the people living in their homes but as the outside air is generally drier in other countries, natural ventilation (opening windows) can work quite well in these cases, but where it is very cold ERV (Energy Recovery Ventilation) and HRV (Heat Recovery Ventilation) are often used in conjunction with a central heating systems where the winter is long and cold as the HRV ventilation systems will recover the waste heat and waste the moisture, where as the ERV will recover the waste heat and moisture and will bring it back into the home making the fresh air more humid. In New Zealand we don’t need this process in most parts of the country.

In both the US and UK they are heating for far longer periods (6 to 8 months, possibly more) of the year and often using central heating in all parts of the home for 24 hours of the day, 7 days a week, where here in New Zealand – on the whole – we tend to have a shorter and milder winter (3 to 5 Months) and often only heating for 3 to 6 hours of each day. Also our roofs tend to get some natural warmth during most days in the winter months, where as the UK and US (in the colder climates) would get very little if any, especially if there is any snow on the roof.

During June and July ’09 (our winter) I have been into many homes where the roof temperature has been over 23 deg C, generally if it is not raining the roof temp is the same or higher than the house temperature, far warmer than the outside temp and far drier than either outside or inside the house (opening windows gives you wind blown moisture and cold air).

Yes I know there are places in New Zealand where you are heating for longer periods of time, and in those areas the heating / ventilation systems need be looked at in a similar manner to parts of the US Europe and the UK, but that is only a very small part of New Zealand.


The question needs to be asked though….

Why are we using studies from both the UK and US to prove or disprove what is good for all New Zealand conditions?  Yes in some cases they are different for starters we (in NZ) Don’t have central heating, It maybe suitable for some parts of the country but for the majority of New Zealanders we really do not need balanced heat exchanger ventilation systems.

Lets discuss it all further, please read the following pages and if you want ask questions or make comment use my blog.

The Need for Ventilation to maintain indoor air quality

Moisture control, airflows and ventilation