A small base for an Aircon Unit

[JohnnyUK]

Hi

We're having a/c fitted on Monday and MrsJohnnyUK insists the unit is put on the ground, as opposed to the external wall.

I've cleared away the existing pea shingle and on the advice of the fitters, put down a couple of bags of Postcrete.

There's still some way to go to make it level with the paving slabs.....ignore the black irrigation tube.

Would you finish with Concrete Mix or Mortar. ChatGPT suggests the latter.

Thanks!

[Ste-EVo]

I'd have thought a bed of concrete, and thats what I would do if it was mine, but im by no means an expert.

[GasEngineer]

Why not use a bit more Postcrete?

[VTC]

Postcrete is meant for underground/inground,
Wickes etc probably sell premix aggregate
add some cement mix etc.

[p1stonhead]

Mine just sits on shingle on rubber feet like this;

[caziques]

Don't forget about the condensate that comes from the outdoor unit when in heating mode.

[Danns]

Although the manuals for the less consumer grade and more commercial models do state 100mm concrete - the feet above + shingle appears pretty standard. Pretty sure the last Electriq one I looked at made no mention - then again it left out a lot of the required commissioning checks for fgas!!

Risk really is ground shifting and unit not sitting level so the condensate mentioned above won’t drain… or ground shifting and force being put onto the copper lines made off into the unit and having the flares leak.

The height can be adjusted /levelled easy enough using the rubber feet too.

End of the day, if you are having a pro install, will be down to them signing off the installer checklist on the installation for warranty etc.

(For mine I did 100mm slab twice the size of the unit with 30mm slabs / stuck to the top with outdoor adhesive as part of the patio.. hindsight, should / easily could have just stuck with the 100mm type 1 + 40mm mortar bed under the slabs)

[Panamax]

It just needs to be standing on something stable, typically a couple of small slabs just sitting there for the purpose. Whether those slabs are standing on concrete or shingle makes no difference. If the unit comes with those rubber feet I guess you rely on those alone. They look to me more like sound/vibration deadening for when the units are standing on a roof but could obviously be used on the ground as well..

[JohnnyUK]

Thanks all - I went with a layer of ready mixed mortar. Not the prettiest of finish - still drying, but I'll tidy up the front edge once fully dry.

I did ask about shingle and the guy pulled a face....we'll see!

Thanks again

John

[biggiles]

Often worth putting a big tube of conduit/pipe up against the wall, rat-proofed, in case you want to run your irrigation pipes through it.

I had a split a/c unit on a back wall - never again - the very slight vibration was noticeable. It's now on a plinth of heavy concrete blocks. As an earlier poster said, watch out for the condensate tube - they always seem to be in a poor place, and you'll want to direct it somewhere (and have enough height to give you options).

[Wildfire]

Mine is the same as the above and sits on rubber feet on the patio no issues.

[Mr Whippy]

Concrete surely is the ‘best’ and whatever you do on top is based on aesthetics?

I’d do concrete, figure out the outline of the feet or whatever, then pea-gravel or shingle around them, so it looks like it’s sat on gravel or a stone slab or whatever, but isn’t really.
Like those drain covers which you in-fill to match surroundings. Make it look posh innit.