The Autumn Changeover: Switching Your Home from Cooling to Heating
Do this over one weekend in September or early October. Three jobs matter most: dry out and store your air conditioner properly (skipping this is why units smell musty next June), test the heating before you need it (a fault found in September is a routine callout; found in December it’s an emergency one), and clear gutters and drains — the highest-value job of the year given this winter’s storm-leaning outlook.
The changeover weekend is the most useful thing a UK household can do for its home in autumn, and most of it is free. Here’s the whole list, in the order worth doing it.
1. Deal with the air conditioner properly
Don’t just wheel it into a cupboard. The single most important step is drying it out.
A portable air conditioner spends its working life condensing moisture onto an internal coil. Put it away damp and you’ve created ideal conditions for mould inside a sealed box, for months, with no airflow.
The routine:
- Run it on fan-only for two to four hours to dry the internal coil. This one step prevents most musty-smell problems.
- Drain the tank fully via the drain plug.
- Clean the filter and let it dry completely before refitting.
- Disconnect and loosely coil the hose — never fold it tightly, which creases the material permanently.
- Store it upright, somewhere dry and temperature-stable.
Our full winter storage guide covers the detail.
2. Test the heating before you need it
Turn it on in September, on a mild day, and let it run for half an hour.
- Check every radiator gets hot all over. Cold at the top means air — bleed it. Cold at the bottom means sludge, which needs an engineer. Completely cold usually means a seized TRV pin, which is often freeable by hand.
- Free stuck TRVs. They seize after a summer fully open. Pull off the plastic head and check the pin moves.
- Check boiler pressure on a combi and top up if low.
- Book the annual service now. Heating engineers are booked solid from the first cold snap onward. September pricing and availability are entirely different from December’s.
Our cold room guide covers diagnosing a room that never warms up.
3. Clear gutters, downpipes and drains
The highest-value outdoor job, and free if you’re comfortable on a ladder.
A blocked gutter overflowing down a wall saturates the masonry. Wet walls conduct heat out far faster than dry ones and let moisture in, so this is simultaneously a damp problem, a cold-room problem and a heating-bill problem.
Do it after leaf fall finishes. Check downpipes run clear to the drain, not just that the gutter looks empty. Clear gully gratings too.
This matters more than usual this year — the Met Office’s position is that El Niño raises the chance of milder, wetter and windier conditions in autumn and early winter, and NOAA has the event at a greater than 90% chance of reaching very strong. Our storm-proofing guide covers the full outdoor list.
4. Draught-proof
The cheapest permanent reduction in heating demand available. Doors first, then windows, then the forgotten ones — unused chimneys, loft hatches, floorboards, service penetrations under sinks.
Seal draughts, not ventilation: never block airbricks serving a room with a fuel-burning appliance, vents to a suspended floor, extractor fans, or trickle vents. Our draught-proofing guide covers the whole job and the safety boundaries.
5. Switch the ventilation strategy
Summer ventilation is about flushing heat. Winter ventilation is about removing moisture without losing heat.
The change: stop leaving windows on the latch for hours, and start doing short, sharp purge ventilation — five to ten minutes with windows wide open exchanges the air without letting the fabric of the room cool. Keep trickle vents open and extractor fans working.
Our condensation and damp guide covers the winter approach in full, and it’s worth reading before the first cold week rather than after mould appears.
6. Reverse the curtain routine
In summer you close curtains during the day to keep solar heat out. In winter you open them during the day to let it in, and close them at dusk to reduce heat loss through glass.
Thermal or lined curtains earn their keep here. Glass is the weakest thermal element in most rooms.
7. Check the loft
While you’re up there putting summer things away:
- Check insulation depth — Building Regulations guidance points to around 270mm of mineral wool. Look for areas pushed aside for storage or disturbed by cabling.
- Look for daylight through the roof, and for water staining on timbers.
- Check pipes and tanks are lagged. Burst pipes are the most common consequence of a sharp freeze, and lagging is cheap.
- Insulate and seal the loft hatch — often a bare board in a rough frame.
8. Prepare for storms and power cuts
- Secure loose garden items — furniture, trampolines, bins, ladders.
- Check fence posts and gates.
- Look at trees for dead limbs near the house or a parked car.
- Torches, not candles, and charged power banks.
- Know 105 — free from any UK phone to report a power cut.
- Sign up for flood warnings if you’re at risk, and check your risk if you don’t know it.
- Register for the Priority Services Register with your network operator if anyone in the household depends on electrical medical equipment.
9. Test the alarms
Smoke alarms and — importantly — carbon monoxide alarms, if you have any fuel-burning appliance. Heating season is when CO risk rises, and this is the one item on the list that’s genuinely about safety rather than comfort or cost.
10. If you’re buying, buy now
Autumn is the right time to buy cooling equipment for next summer, and the right time to buy a heat pump unit for this winter.
Demand for portable air conditioners collapses after September and doesn’t recover until May, so autumn and winter pricing is genuinely better than spring — and during a heatwave, UK retailers have repeatedly run short of stock. Our buying timing guide and Black Friday guide cover the calendar.
ElectriQ Eco Silent 12000
Works from the week it arrives
53 dB
A-rated
Heat pump
The unit that makes an autumn purchase immediately worthwhile rather than a deferred one — reverse-cycle heating through winter, cooling through summer. A-rated across both. Suits rooms up to around 28m². Roughly 35kg, so plan a two-person carry.
The weekend plan
| When | Jobs |
|---|---|
| Saturday morning | Gutters, downpipes, drains, gully gratings |
| Saturday afternoon | Secure garden items; check fences and trees; loft check |
| Sunday morning | Test heating; bleed radiators; free stuck TRVs; book boiler service |
| Sunday afternoon | Draught-proofing; air conditioner dry-out and storage; test alarms |
Frequently asked questions
When exactly should I do this?
Mid-September to mid-October for most of it. Gutters are best left until leaf fall has finished, which may push into November depending on nearby trees.
Should I leave my air conditioner set up in case of a late warm spell?
Reasonable through September, and increasingly so given how late UK heat has been arriving. Just do the dry-out properly whenever you do put it away — the storage step matters more than the timing.
Is it worth servicing the boiler every year?
Annual servicing is the general recommendation, and it’s often a condition of manufacturer warranties. Book it in early autumn — availability and pricing in September bear no resemblance to December’s.
What if I find a problem I can’t fix?
That’s the point of doing it in September. A heating fault found now is a routine appointment; the same fault in a December cold snap is an emergency callout with emergency pricing, if you can get one at all.
Compare current prices, stock and reviews on heat pump air conditioners at Amazon UK. Autumn means normal prices and full availability.
Sources
- Met Office — El Niño and the UK (higher chance of milder, wetter, windier autumn and early winter)
- NOAA Climate Prediction Center — ENSO Diagnostic Discussion
- Energy Saving Trust — Draught-proofing
- Energy Saving Trust — Roof and loft insulation
- Gas Safe Register — Carbon monoxide safety
- GOV.UK — Check long term flood risk
- Energy Networks Association — Power Cut 105
Related reading: our storm-proofing guide, draught-proofing guide and storage guide.
