Evaporative Cooling Ceiling Vents

Evaporative Cooling Ceiling Vents – Thermal image of evaporative coolers in winter, with precious heat escaping from the evaporative cooling unit on the roof.

There is no doubt that evaporative cooling can be an inexpensive way to cool your home, but in Melbourne and other climates around Australia there can be some serious drawbacks that can be very expensive. These disadvantages are not considered before an evaporative cooler is installed or sold to a consumer interested in keeping cool in the summer.

Evaporative coolers can add an additional 20-40% more air loss in a home. Using the fan door test, we found that removing an evaporative cooling system with a mechanical damper can contribute to about 20% of the air losses in a house, which is a huge overload in winter for heating.

X Square Ceiling Vent Cooling Vent Evap 4way Mdo Ceiling Vents 406x406mmm

Based on the Reference Meteorological Year (RMY) weather file for the major cities of Australia (regional office stations), over 8760 hours in a year, the table below shows how many times a year heating or cooling is required:

Land Zuel vun Stonnen mat Temperaturen ËNNERST 10C D’Zuel vun Stonnen mat Temperaturen IWWERT 30C Melbourne1336176 Sydney33168 Canberra3192109 Hobart360917 Adelaide1021484 Geelong2342155 Woolongong58344 Bendigo9 Bribane36091640914409 Per7409144091 Per74091 Per74091 Per7409136091 Per7409136091 Per740913609 Per7409

CSIRO has provided the number of hours in various cities around Australia with temperatures below 10°C and hours above 30°C

Perth has a different ratio to most other Australian cities with low humidity, so it could be assumed that moving to an airtight building envelope versus continuous ventilation is less beneficial.

Ducted Air Conditioning Vs. Evaporative

When you look at the big picture of heating and cooling, the money you save from cheap refrigerants is well and truly offset by a less efficient home heating system. Hot air rises and evaporative coolers are usually located in the ceiling of each room. For example, have you ever noticed in the summer that the top floor of a two-story house gets hot and the bottom floor stays cold? In winter, an evaporative cooler produces the same effect but worse because this heat goes outside.

The other problem against evaporative cooling is how many of those limited heat hours above 30˚C have high humidity? Evaporative cooling does not work very well with high moisture content in the air.

If you take the draft side out of the equation and cover your logs every season, you still have areas on the ceiling that are not insulated for heating in the winter. It is important to have your evaporative cooler professionally cleaned every year, which is another cost of using this technology. These problems never go away and are additional costs that are taken into account in the operation of the system.

If you already have an evaporative cooler or still want to follow this path, here are some things to think about.

Aerocool Trophy Downdraft 8

If you already have an evaporative cooler, cover the discharge logs with contact every winter or shop around because there are some great covers to reduce the effect of the draft through these systems.