Evaporative Cooling Installation

How ducted evaporative cooling works

A roof-mounted unit draws outside air across wet pads. Water evaporates, that evaporation absorbs heat, and the cooled air is pushed down through ducting and out through ceiling outlets. Because the system is continuously introducing outside air, it needs somewhere for that air to go — windows or vents cracked open on the far side of the rooms you are cooling.

That single characteristic explains both its strengths and its limits. Running cost is low, because the machine is essentially a fan and a water pump rather than a refrigeration circuit. The air is fresh rather than recirculated, which suits people who dislike a closed-up house. And on genuinely dry days it delivers a substantial temperature drop for very little electricity.

When evaporative is the right choice

We will recommend evaporative when the numbers and the household both point that way. That usually means a home where running cost matters more than holding an exact temperature, where opening windows is practical and secure, where there is decent roof space and a workable position for the unit, and where the household is realistic about humid days.

It is also frequently the right answer when an existing evaporative system has simply reached the end of its life. If the ducting is sound and the home has been comfortable for fifteen years, a like-for-like replacement is a far smaller job than a changeover and costs a fraction of it. We are not going to talk you into a refrigerated system you did not come looking for.

Sizing, outlets and pad types

Sizing an evaporative system is about airflow rather than kilowatts. The unit has to move enough air to change over the volume of the house several times an hour, and the outlets have to be positioned so that air sweeps through living areas toward an exit rather than short-circuiting back out of the room it entered. Undersized units and badly placed outlets are the two most common reasons a system disappoints, and neither is fixable with servicing afterwards.

Pad type is worth a decision rather than a default. Aspen pads are cheaper up front and need replacing more often. Rigid media pads cost more initially, last considerably longer and generally cool more effectively, which usually makes them the better value over the life of the unit — particularly on harder water.

What we check before quoting

Roof type and pitch, and whether the unit's position gives clear access for servicing later. Roof space for the ducting run and the outlet layout the house actually needs. The water connection and drainage for bleed-off. Power supply at the unit. And where the home already has ducting in place, whether it is sound, correctly sized and worth retaining.

We quote fixed-price once we have looked at all of that. A number given over the phone before anyone has seen your roof is an estimate wearing a disguise.