Home insulation: how to stop your bills going through the roof | Energy bills

If you have been working at home this winter in six layers of clothes and a hat, plus an ever-present hot-water bottle, you have almost certainly been wondering how to better insulate your home and make it cheaper to heat. After all, nothing focuses the mind like gas and electricity bills of £2,000-£3,000 a year.

But have you actually tried to find out in detail how to bring down your bills without spending a fortune on a complete rebuild? I have, and I can tell you that it’s surprisingly hard to get independent advice that goes beyond trite calls to upgrade your loft insulation.

While there are plenty of energy measure installers out there, how do you know if they are any good? Is what they are proposing or selling the best option for your house? Will they still be there in five years’ time if there’s a problem?

I decided to have a proper assessment done on our house, and the firm I chose has just come back to me about what options are available – and how much it is likely to cost.

There are a number of government and local schemes aimed at helping to make homes more energy-efficient, thereby bringing down bills, although these are typically restricted to certain groups, such as people on low incomes.

Miles Brignall outside his home
Miles Brignall outside his home in Hertfordshire. Photograph: Clare Brignall/The Guardian

In April, the government will unveil Eco+, a £1bn scheme that it has previously said will result in hundreds of thousands of homes across the country receiving new home insulation, “saving consumers about £310 a year”. It will focus on installing lower-cost measures such as loft and cavity wall insulation. Although the details are still in short supply, the government has said Eco+ is aimed at helping a wider customer base who are now not eligible for support, particularly people in energy-inefficient homes – those with an energy performance certificate (EPC) rating of D or below – and in the lower council tax bands.

Eco+ will run alongside Eco4, which already offers help to poorer households, and the boiler upgrade scheme that offers £5,000 to those installing an air source heat pump.

Unlike the disastrous green homes grant scheme that it replaces, Eco+ is set, rather worryingly in my opinion, to be carried out by the big energy suppliers – firms that are already understaffed and often struggling to answer the phones to their existing customers. The emphasis looks likely to be on low-cost solutions, when what the UK really needs is something more substantial.

So, what happens if your home already has basic insulation, you are not on benefits but you want to cut your bills and your carbon footprint?

Mineral Rockwool insulation on an attic floor
Does your house need better insulation? Photograph: Brizmaker/Getty

To put you in the picture, we live in a bog-standard, medium-sized family house that was built on a Letchworth (Hertfordshire) estate in 1980, one of millions of similar homes across the country.

It still has the original cavity wall insulation and slightly tired-looking but functioning double glazing. It even has the original 1980 Ideal Concord boiler that is surprisingly efficient and refuses to die. We installed a wood-burning stove – yes, I know – and the loft is fully insulated to the required depth of 300mm.

When the heating or the stove is running, it’s all quite toasty and, despite the age of our boiler, it costs about £1 an hour to run the heating with only half the radiators and rooms in use – the same as friends who have newer combi boilers.

But as soon as the heating goes off in cold weather, as it has been this week, you can feel the temperature dropping. I suspect we need more sophisticated insulation, and ultimately to replace the old boiler and the wood burner; but how, and with what?

After what felt like a lot of fruitless phone calls to find an expert, step forward Becky Lane, who runs Furbnow, a firm set up to fill exactly this space in the market. She generously agreed to allow Guardian Money to trial the service and, a few weeks later, one of her home assessors, Adrian, was dispatched to Hertfordshire, where he spent a few hours crawling all over our house.

A borescope inspection of our cavity wall soon revealed that much of the insulation material originally put in – probably in 1980 – had slipped and would benefit from being topped up.

Adrian was somewhat surprised that we were still running a 40-year-old boiler but, as I explained, there didn’t seem a lot of point in replacing it with a £2,500 combi that would last 10 years and give fractional savings in lower bills.

So what did Furbnow’s report say? We got an EPC of D, which was better than I expected. Aside from topping up the cavity wall insulation, which the company says should cost about £1,500, the most interesting recommendation was to insulate the floors downstairs, which are all solid concrete. I was also told we need better ventilation such as window trickle vents.

“It might sound counterintuitive, as heat rises, but you can typically save 10-15% with proper floor insulation. It makes sense to put it in at the time you change your carpet or wooden flooring. In your house I would expect it to cost about £5,000 but it would make a significant difference,” Lane says.

Her other big recommendation was to install a solar PV (photovoltaic) system on the roof and a battery in the garage, which will bring down our electricity bills and carbon footprint significantly. With a spend of about £10,600, it looks like we could become about 65% self-sufficient in electricity, saving £700 a year. This would get our home up to an EPC rating of C – a minimum of where most of us need to be.

In the long run, when our boiler does give up the ghost, it probably makes sense to take the government’s £5,000 grant towards installing an air source heat pump at a typical cost of £10,000.

Two men in hard hats handling panels
Solar panels being fitted to a house roof in Wales. Photograph: Chris Howes/Wild Places/Alamy

I had always suspected that we would not be warm enough with an air source heat pump, and that all our radiators would need to be replaced; however, the report suggested that we should be fine with our existing set-up after some energy efficiency improvements.

Furbnow offers various follow-up services, and will carry out the work on your behalf using its own verified contractors – which will appeal to many given the reputation of the energy-installing industry. Its staff will also check any quotes the householder gets themselves to make sure the price is fair and that the materials being used are the most suitable, and it is this route I will probably go down. I just need to find the £12,000 that it will cost to upgrade the basic insulation I have and install the solar panels and battery. I will return to the latter topic in the coming weeks.

Furbnow visits by an accredited retrofit assessor start at £350 plus VAT. In general, consumers should be looking to use MCS-accredited installers when undertaking work in this area. For more information go to Mcscertified.com.

Cheap cuts: from putting down underlay to closing curtains

If you don’t have the cash for a green makeover or are renting, there are still cheap, or even free, steps to take to cut energy bills.

Letter from energy company showing new direct debit payments with large increases in gas price -
There are ways to cut your energy bills even if you do not have the cash for a green makeover. Photograph: Carolyn Jenkins/Alamy

Richard Fitton, a professor in building performance at the University of Salford, says people can save money without retrofitting the whole house, just by following simple energy-saving tips.

They are backed by research at No 1 Joule Terrace – the two-up, two-down house built inside a chamber at the university. Called the Energy House, this Victorian “property” resembles a fifth of UK housing stock and, with more than 200 monitoring points inside, is used to test new technology – from air source heat pumps to smart meters – in real-world conditions.

Last month the university unveiled the Energy House 2.0, a temperature-controlled chamber with two new-build homes inside that will be used in a similar way to test the technologies that will make our homes greener and cheaper to run in the future.

Take the ‘money saving boiler challenge’

Unlike the ice bucket challenge, videos of you doing this are unlikely to go viral on social media but turning down the temperature of your combi boiler makes it work more efficiently, and is estimated to save the average household about £112 a year.

Combi boilers work best when they heat the water that goes to the radiators at 60C or below (called the flow temperature); but in most homes they are set at 70-80C. There is a step-by-step guide on how to adjust the temperature on the money saving boiler challenge website.

“You could walk into your kitchen now and do that change in about 20 seconds and come out with savings of 10% to 15% depending on how your boiler is set up,” Fitton says. “We did the fundamental research on this [at the Energy House]. It’s a really easy one to do and it works.”

A window with curtains closed
Closing curtains and blinds at night can save 2% on annual heating bills. Photograph: Terry Mathews/Alamy

Stop heat escaping through the floor

If fitting a new carpet or floor, also give serious consideration to what is usually an afterthought: the underlay. It is made up of millions of tiny fibres that act as natural insulators, making it an effective barrier to heat loss.

“If you put a decent-quality underlay down when you change your carpet, it’s going to save you about 5% on your energy bills but also increase the thermal comfort in that room,” Fitton says.

“It stops the cold air coming through and keeps the surface warm, so your feet feel nicer, basically.”

Close the curtains

Another simple energy-saving tip given the thumbs up in an Energy House study is catchily titled “the thermal performance of window coverings in a whole-house test facility with single-glazed sash windows”.

Fitton says: “By trapping a layer of air between the curtain and the window, it creates a kind of flimsy double glazing-type setup.

“Drawing your curtains and blinds every night on a typical Victorian terrace like the Energy House is going to save you about 2% of your heating bill every year. That’s just by using the things you already have.”
Zoe Wood

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