Net zero makeover: could a heat pump help me reduce my energy bills?


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Jun 23, 2023

Net zero makeover: could a heat pump help me reduce my energy bills?

Net zero makeover: Our tetraplegic reader needs warm surroundings, but lives in a '50s home Would you like to take part in a free net-zero home makeover? Email [email protected] with the subject

Net zero makeover: Our tetraplegic reader needs warm surroundings, but lives in a '50s home

Would you like to take part in a free net-zero home makeover? Email [email protected] with the subject line: “Give me a home makeover”.

Gordon Cruickshank has lived in a quiet, palm tree-lined cul-de-sac in Wimbledon for 25 years. A motoring journalist, Mr Cruickshank, 68, continues to work three days a week for Motor Sport magazine, which is nearing its 100th birthday.

Mr Cruickshank has used a wheelchair since 1989, when he broke his neck during a car crash. He shares his bungalow with a series of live-in carers.

“Like many tetraplegics, I can’t control my body temperature so I need warm surroundings,” he says.

“In fact, I spend the winter huddling by a gas-guzzling coal-effect fireplace, or in the small study where I work, and my gas bill is vast.”

Mr Cruickshank pays quarterly for his energy usage – his smart electric meter indicates he used 1,300kWh in the last three months of last year, which at the Energy Price Guarantee rate of 34p/kWh has cost him around £450.

His gas meter, which isn’t smart, shows he paid £1,033 for the quarter at the 10p/kWh EPG rate.

A previous attempt at an energy assessment of the “heat sink” bungalow resulted in a quote of £520,000 to fix the problem.

He is interested in an air-source heat pump but is worried that the green technology, which can take longer to heat a room than a gas boiler, will not give him the immediate warmth his condition requires.

The heating controls in Mr Cruickshank’s home are also designed to be accessible to him, leaving some confusion over which options remain valid.

“I just want to keep better temperature controls around the house – and reduce my bills”, he says.

As part of Telegraph Money’s Net Zero Home Makeover series we sent two experts to assess the property, and provide their top tips.

Now read: How to keep your house cool during the summer

I visited Mr Cruickshank in his Wimbledon bungalow on a hot sunny Monday evening with my infrared camera. His 1950s bungalow is at the end of a very quiet secluded cul-de-sac surrounded by trees and is well lived in and tailored to his disability.

He added an extension 25 years ago and showed me all the plans which included the level of insulation applied at the time – cavity wall insulation, loft insulation, double-glazed windows and more.

Mr Cruickshank’s disability means his body can’t regulate his temperature so it’s really important that a full survey delivers the best heat solution for him.

The home is heated with a gas combi-boiler, two fireplaces and a mix of original radiators and some which were replaced 25 years ago. However, he has begun to consider switching to an air source heat pump.

We started in the loft, which has between 100mm and 200mm loft insulation as part of the extension. The insulation was updated 25 years ago and now has a lot of gaps and has moved over the years. So this needs a good overhaul.

As it was boiling outside, my infrared camera worked in reverse and we were able to see hotspots around the ceiling and through the original thin wood front door.

Once winter comes, these spots will be the areas where the house loses a lot of heat. The front door needs to be replaced, along with all the other spots where the insulation had gaps.

Even though the wooden-frame double-glazed windows are 25 years old, most of them look good – a testament to Mr Cruickshank looking after the house properly for many years.

There are just a few on the southern side that now have condensation – this will have an impact on the insulation capability and they should be replaced eventually.

Speaking of windows, a skylight in the centre of the property is losing a lot of heat, which will have a huge impact on costs as it’s not in a room that could be closed off.

Gordon will need to decide if it’s worth losing some light for some warmth or get a fitted cover for the winter.

Extraction fans are essentially just a pipe for heat to exit so there’s no surprise that the bathroom and kitchen have huge losses here. He should get a flap to help in the winter.

The garage isn’t heated or insulated. As the house wraps two sides of the garage then the heat loss in the winter is going to have an impact. It looks like the internal walls only have 50mm cavity insulation, so any extra insulation to this would be worthwhile.

We looked at where we could locate an air-source heat pump, where to put a hot water tank and if he would need to change the radiators.

There’s a narrow passage from the garage door into the garden where it’s possible the heat pump could be located.

There’s not a lot of space for a hot water tank, however it may be possible to fit a Sunamp unit [a thermal storage unit] instead of a hot water tank in that cupboard which would be a great solution.

For ease, we would suggest switching all the radiators so they are updated and uniform.

If he did switch to a heat pump, he could save a lot of money by removing his gas fires, capping the gas (therefore removing the gas standing charge) and switching to a combination of heat pump, electric blanket (for a boost of cheap heat) and a couple of plugged-in infrared panels that he already uses for more localised heating.

Now read: Six reasons not to buy a heat pump

On approaching the door, I immediately noticed the tell-tale drill holes in the cavity brickwork: cavity wall insulation has been installed, so this is a positive start to this energy performance certificate survey.

The owners had prepared for my visit with a full set of plans showing two substantial 1998 extensions added to the original 1959-built property.

The measured survey reveals a substantial “heat loss perimeter”, which is the EPC measurement for walls exposed to either the outside or any unheated space.

The perimeter is increased by having two walls adjoining a large unheated garage. This, combined with the substantial number of older-style timber-framed double-glazed windows installed in 1998, will make the owners feel that the house is permanently cold.

Replacement with new UPVC-framed double or triple-glazed windows will add only 1 EPC point as the property has existing double glazing. However, the UPVC frames will help improve the lack of draught-proofing often found with older timber windows.

With retrofitted cavity wall insulation to the original building and the newer extension having been constructed with insulation, what options does the owner have to improve the thermal properties of the walls?

External wall insulation can be an effective solution and provide an EPC uplift of 2 points. However, with an annual fuel saving of just £165.84 and a high capital cost, this type of insulation shows better results with a solid brick-built property.

A quick fix for any draughty house that can provide a 1-2 point EPC improvement can be permanently blocking unused open fireplaces.

Just remember that chimney balloons won’t count as a permanent fix, so consider installing a permanent solution.

I spotted two chimney stacks on arrival at the property. While one fireplace had been blocked with a balloon, the other remained in use with an open gas fire.

A trade-off exists between the benefit of the local heat provided and the heat loss when the gas fire is not used. With the right programme of improvements in place, the open fires should be dispensed with in due course.

There are some real plus points to this property: the loft inspection reveals a healthy 300mm double layer of Rockwool insulation; however, there was no access to check the flat roof sections of the extensions.

A modern A-rated condensing combi boiler has been fitted, and this has zone control to ensure that rooms that are not in use are not using unnecessary fuel.

The weather compensator will assist in maintaining a constant internal temperature even when external temperatures fluctuate. Overall, I gave this property an EPC rating of C-71.

Now read: How to keep your house cool during the summerNow read: Six reasons not to buy a heat pump