Heat pump covers — how to choose one and what to build it from

A heat pump sits where you see it most: against the garden wall, next to the terrace or at the front of the plot. It is bigger than an air conditioner, it stands on the ground, and it has its own working rhythm — the fan runs in winter too, and defrost water drains from underneath. A heat pump cover has to hide all that without getting in the unit's way.

This is a guide to choosing one: where to take the measurements from, how much clearance to leave, what to build it from, and what not to do if you do not want a higher electricity bill.

Screen, cover, enclosure — is it all the same?

In shops these words mean roughly one thing, but two ideas are worth separating:

• a screen or cover — a louvred structure around the unit, closed on three sides, open at the back, with gaps between the bars,
• a full enclosure — a closed box with no openings.

For a heat pump only the first one is relevant. A full enclosure restricts airflow through the exchanger, and that is not an aesthetic question but an energy one. A unit that draws in its own exhaust runs longer for the same result.

Where the dimensions come from

Three sets of numbers, none of which can be skipped:

1. the outdoor unit's size — width, height and depth from the plate or the manual,
2. the clearances the manufacturer requires — those are binding, not our habits,
3. the space actually available on the plot, including a walkway in front of the unit.

Heat pump makers usually ask for more room than air conditioner makers. Common figures are 10–20 cm at the sides and 30 to 50 cm in front of the air outlet, plus enough above the unit to lift the service cover. Check your own manual — the difference between makers can be twofold.

The cover's size is the unit's size plus those clearances. Not the other way round.

Bar spacing, and where the air really goes

The gap between bars matters less than people think — provided the back stays open and there is room in front of the outlet. With horizontal bars 100–200 mm wide, a gap of around 20 mm is a good compromise: from two metres the cover reads as a solid wall, while air passes freely.

A tighter pattern looks lighter but needs more parts and more assembly. A looser one shows the unit. That is an aesthetic decision, not a technical one — as long as you are not closing the structure on all four sides.

What to build it from

Powder-coated aluminium. Does not rust, is light and needs no maintenance. A powder coat in any RAL colour holds for years outdoors. The most expensive to buy and the cheapest to own.

Laser-cut steel. Gives the most freedom in the pattern, from plain bars to cut-out panels. Heavier, needs proper corrosion protection, but nothing beats it for decorative cut-outs.

Timber. Cheapest and easiest to get, but the worst match for a heat pump: defrost water, shade and limited airflow are exactly the conditions in which timber moves and greys. After two or three seasons it needs oiling or replacing.

Four mistakes that cost money

• Closing the structure on all four sides. The back must stay open. That is the one rule with no exceptions.
• Placing the cover too close to the outlet. The air bounces off the bars and returns to the unit.
• No service access. The installer must reach the connections and the cover plate. A bolted structure that comes apart solves this permanently.
• Leaning the structure against the unit. The cover must stand on its own. Vibration carried into the pump casing is noise you cannot silence afterwards.

Standing it up — the part people forget

An air conditioner usually hangs on wall brackets and its cover can be light. A heat pump stands on the ground, so the cover is free-standing and needs its own base: adjustable feet on paving or on a concrete pad. The structure catches wind across the whole louvred surface, so the frame has to be stiffer than on a wall-mounted cover.

Drainage is worth a thought too. Defrost water collects under the pump in winter — if the cover stands on paving with no fall, a freeze turns that into an ice rink reaching under the unit.

Colour

RAL 7016 anthracite is the most common choice, and for a reason: it is the colour of window frames and gutters on most new houses, so the cover blends in instead of standing out. The second approach is matching the fence — if it is built from aluminium profiles, a cover from the same profile family looks like part of it rather than an addition.

In short

A good heat pump cover is one the unit does not notice: open at the back, set at the distance the manual asks for, demountable for servicing and standing on its own feet. The rest — material, bar spacing, colour — are aesthetic decisions you can make freely.

If you want the dimensions checked against your own unit, describe it in your enquiry along with its size — we will work the cover out from those numbers, not from a catalogue size.