Will a cat flap destroy BER rating / insulation?

spudrick · 07-02-2023 06:22PM #1

We're in the process of buying an A2 rated house in a new development, with air to water heating from a heat pump. In our current house we have a cat flap in our back door which involved replacing a pane of glass with one that had a flap built into it, but the new house has pretty much floor to ceiling single pane glass for the back door with energy efficient glazing, and I understand strong insulation is particularly important when dependent on air to water heating.

So is a cat flap a no go or can it be done in a way that doesn't have a negative impact?

Ray Palmer · 08-02-2023 12:54PM

A cat flap is just like leaving a window open and will always effect the heating. It won't be any different due to the heating type. Most cat flaps are made of thin plastic with litterally no insulation value. We had one and got rid of it due the noticeable draft it caused. It will be more noticeable if the rest of the house is airtight.

KLF · 08-02-2023 03:20PM

We also have an A2 house and had a new pane fit in with a cat flap. Yes, it lets a bit of draft when the wind is blowing head-on but less than the kitchen hood vent that had no back draft fitted but yet the developer still easily got the BER A2 sign-off. Have since rectified that myself.

The BER rating is set at a point in time so that won't change but yeah you'll be sacrificing some air tightness. We haven't found out the ground floor heating thermostat firing much more than usual and stays around 20/21c.

The convenience more than makes up for it.

Victor · 09-02-2023 11:58AM

Potentially add a porch, so the cat can have shelter / food / water or create a cat-sized porch with two insulated flaps.

Note that when moving house that some animals will try to run away to their old house.

o1s1n · 09-02-2023 04:04PM

Indoor only cats live much longer, healthier lives than outdoor cats and don't impact your BER rating, just saying 😁

heffo500 · 09-02-2023 04:11PM

Maybe install something like this:

PetSafe Extreme Weather Energy Efficient Aluminium Pet Door for Cats and Dogs – Insulated Flap System – Large

Will a cat flap destroy BER rating / insulation?

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