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R290 Heat Pump and Foundation Air Bricks

L8Again · 2026-01-15T09:35:32Z

I am going around in circles. My property has foundation air bricks sited below the damp proof layer to ventilate the void under the property's suspended concrete floor. I have spoken to the UK Technical Team for a well known German HP manufacturer and they are adamant that the air bricks need to sit outside of the R290 protection zone. An Octopus Energy representative has posted on another forum 'Air bricks are not a concern.' This is reflected in the following guide: Clearly, both HP manufacturers cannot be right. Searching for Regulations on this is something of a Fools Errand. The Heat Pump association states the following: 'Where defined within the manufacturer safety-related protection area, there must be no:- - permanent or temporary sources of ignition during normal operation, such as, but not limited to, open flames, electrical systems, sockets, lamps, and light switches, electrical housing connections, sparking tools, or objects with high surface temperatures, etc. - building openings, such as windows, doors, light shafts, flat roof windows, and ventilation system inlets and openings, - property boundaries or neighbouring properties, walkways and driveways and public access areas - ground depressions, dips or low-lying recesses, and any water or sewage services, and no open pump shafts, etc.' I am considering either a Stiebel Elton or Valliant R290 heat pump but air bricks would be an issue. The irony here is that a Cosy heat pump safe zone would just fit between two air bricks. Any thoughts/advice or should I give up and look at a R32 filled heat pump?

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Air Source Heat Pumps (ASHPs)

Last Post by petch 5 months ago

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petch

(@petch)

Active Member Member

Joined: 5 months ago

Posts: 14

11/02/2026 7:17 pm

I have been having fun and games whilst getting surveys and quotes done for an ASHP install, and the one thing that is coming up time and time again as an issue is the installation location. It's under a window, there are some air bricks, there's an open drain, there's a neighbour's window.

I got so fed up I've gone and downloaded the instruction manual for my favoured ASHP, the Grant R290 12kW, and found the following

Air bricks are permitted anywhere within or outside the ventilation zone of the Grant Aerona 290 heat pump, including directly behind it.

It's on page 23 of the installation manual.

Other than that, doors can't be within 300mm and open drains can't be within 500mm. Windows aren't a concern other than for noise. As far the the neighbour goes, it's the quietest (on paper) ASHP I've found and comfortably passes the sound calcs I've done myself

Now to just find a competent, competitively priced installer who is comfortable following the manufacturer's guidance and not some mythical regulations that seemingly do not exist! I'll keep my eye out for unicorns and flying pigs whilst I'm at it.

👍

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