Heating and cooling in PerthDry summer heat, and winter nights that still need a heater.

What's different about heating and cooling in Perth?

Perth's summer heat is dry heat. Bureau of Meteorology averages at Perth Metro give a mean maximum of 31.4 degrees in January and 31.7 in February, with average afternoon humidity of 39% and 38%. Dry air is exactly what an evaporative cooler needs, and CHOICE rates evaporative as most effective in hot climates with low humidity.

Your suburb changes the picture. January averages 33.6 degrees at RAAF Base Pearce and 33.0 at Gosnells, but 29.8 at Swanbourne on the coast. On most summer afternoons the south-westerly sea breeze locals call the Fremantle Doctor arrives, and temperatures often drop under 30 a few hours later.

Winter is the quiet season, not an absent one. Perth Metro's July mean minimum is 8.1 degrees, and the city drops below 2 degrees about four times in an average year. A system that only cools leaves you needing something else for those months.

The heating and cooling jobs that come up most in Perth

Evaporative cooling and its servicing. In October 2006 the ABS found 71% of WA households used an air conditioner or evaporative cooler, and ducted evaporative (32%) was the most common type, ahead of reverse cycle splits (25%). Roof-mounted coolers need their pads, pump and water system looked after, ideally before summer. See evaporative cooling in Perth.

Reverse cycle, for both seasons. Splits and ducted reverse cycle cool with the windows shut and heat in winter. Seeley, which makes both kinds, says reverse cycle is the more flexible option for humid, coastal and mixed weather.

Gas heater servicing. The same survey found 46% of WA households with heating mainly used gas, against 21% using reverse cycle. Those heaters need a licensed gasfitter's check before the cold weeks.

Coastal outdoor units. Close to the surf, placement and corrosion protection belong on the quote and in every service.

Who's allowed to do the work in WA?

Two sets of rules apply. Anyone handling refrigerant needs an Australian Refrigeration Council licence, and in WA the new switchboard protective device and fixed wiring for an air conditioner count as electrical installing work. That needs a licensed electrician employed by a licensed electrical contractor.

WA electrical contractors must show their licence number, which starts with EC, on their ads, vehicles and business cards, and Building and Energy has an online search to check it. Gasfitting for heaters falls under a Class G permit. The WA licence page and our licence guide go further.

When you're ready, tell us the job and your postcode. Licence-checked Perth installers who specialise in that kind of work will see it, and only the one who takes it gets your contact details. If no Perth installer has taken it within 48 hours, installers elsewhere in Western Australia may see it too.