Why isn't my house getting warm enough?

Updated 29 September 2026

Short answer: check five things: where the room sensor sits, the schedule, any change to the flow settings, the radiator valves and the power.

The sensor.

The heat pump heats until the room sensor (your Cosy Pod) reads the target. Next to a front door it reads cold and over-heats the house; near a cooker or in sun it reads warm and stops early. Put it somewhere with a steady temperature.

The schedule.

A heat pump warms slowly, so the house needs to start warming well before you want it warm. Very short warm periods may never get there.

Flow settings.

If the minimum or maximum flow temperature — how hot the water going to the radiators is allowed to get — was lowered after installation, it may no longer be enough on cold days.

Radiator valves.

Keep the valves on the radiators open. A closed valve stops hot water reaching that radiator.

Power.

Check both the indoor and outdoor units are on and the app is connected, then look for a tripped switch in the fuse box.

Also bear in mind heat pumps are usually designed for around 18°C in halls and landings and 21°C in living rooms, so a hall set to 22°C may never reach it.

If none of this helps, Octopus has a Cosy support page with its aftercare contacts. Snugdays is independent and can't fix the heat pump itself.