Heat pumps on the Suburb

This technology can slash your home's carbon emissions, but a lot of information online is old or inaccurate. Jonathan Waxman and Gren Manuel demolish the myths and give an update on their use in HGS

Imagine scientists invented a machine that could generate renewable energy from nothing more than air. Imagine it could provide hot water and central heating for a whole house – and it was no larger than a garden barbeque. 

Imagine no more. That invention is the heat pump and houses across the Suburb are installing them, making a massive cut to their CO2 emissions. The Trust is seeing a sharp rise in applications to install one, and they are getting approved. 

The gas boilers that heat most homes in the Suburb are on their way out. Government policy will see them banned for sale in 2035. And quite right too. They’re a 20th-century solution to our heating problems, belching out greenhouse gases, their emissions made worse by the poor insulation of many Suburb homes. 

Using energy data for two archetypal Suburb properties – a modest cottage in Oakwood Road and a larger home in Litchfield Way – we analyse that both have energy use around twice the size of comparable homes elsewhere in the UK. That’s twice the cost, of course. And also, twice the carbon emissions.

 In HGS, we burn approximately 160,000,000 kilowatt hours of gas yearly to heat our homes. 

That is 30,000 tonnes of carbon dioxide added to our atmosphere and way above the average UK home per square foot. Indeed, we live in HGGS – the High Greenhouse Gas Suburb.  We must bring those figures down and eliminate them – get them to zero! The UK government wants to do that by 2050; we at HGS REACH think the Suburb should aim for 2040. After all, we don’t want to regularly bake as we did this summer (triggering further subsidence problems as our clay dries); we also don’t want to repeat the flooding of Summer 2021. We also don’t want Vladimir Putin to have the power to raise our household energy bills, like the 54% coming in October. 

How heat pumps work

Heat pumps work because, even on the coldest days, there is still plenty of thermal energy in the air or ground. They function like a reverse fridge, pumping this heat (hence the name) into the home to run central heating or provide hot water. You’ve probably read about them in the papers, some of which delight in running articles labelling them as useless, unreliable, noisy, or expensive.  We’ll examine each of these allegations in turn: 

  • Useless? They heat more than half the houses in Sweden. If they can heat homes in Sweden, they can heat homes in London. A handful of Suburb homes are using them, kept toasty warm on cold January nights. This myth is busted. 
  • Unreliable? Early heat pumps had problems, yes. But so did the first combi boilers. A new, well maintained unit should be very reliable. Would the Swedes risk freezing to death by installing tech that would break down in their near-arctic winters? No. Another myth busted. 
  • Noisy? The noise issue requires more careful attention. Their fans hum, so to avoid problems with neighbours, they should be sited away from a boundary, as noted in the Trust’s guidelines. The noise, such as it is, is most noticeable when they are running hard, heating a home on a cold winter’s night. It’s unlikely your neighbours will be enjoying dinner in their garden at that time. If you’re concerned about noise, contact us below, you can visit a house with heat pumps and test if you can hear a few metres away. 
  • Expensive? The picture here is more complex and changing. Cost depends on the house size, which affects the unit size. (Here, for simplicity, we will talk only about heat pumps that collect heat from the air, which are the cheapest and most common). 

Installing your first heat pump may cost two or even three times a new combi boiler.  One reason is that they are mechanically more complex than a combi boiler – that is slowly improving. The other is a shortage of qualified fitters, keeping fitting costs high. 

The government is attempting to fix this by offering grants that cut the price of new installations of air source heat pumps by £5,000 to stimulate increased demand and training. (Search ‘boiler upgrade scheme’ online for more info.) With this grant, the cost of an air source heat pump will be close to that of a new combi boiler. But there is another issue very relevant to HGS: the heat output is different.

Combi boilers pump water at up to 75 degrees C. Heat pumps are more efficient at 45 or 55 degrees – still hot enough for a shower but potentially not enough to fully heat a badly insulated house with small or inefficient radiators. Unfortunately, many of the Suburb’s 5,000 homes fit that description. 

A difference of degree

We at HGS REACH don’t have firm data but reckon most Suburb homes may need an insulation upgrade if they get a heat pump – maybe reducing heat loss from windows and improving loft insulation. They’re a good idea anyhow. But it does underline that installing a heat pump for the first time isn’t just a straight swap for a combi boiler. 

The engineer needs to assess heat loss in the home and find an appropriate place for the external unit which extracts the heat from the air.  Small cottages in HGS may struggle to find a good place to house the external heat exchange unit; a few houses may need some rework to their heating pipework. 

It’s important to note that heat pumps require electric power. So, your gas bill for heating and hot water will drop to zero, but your electricity bill will rise. However, by 2021 UK’s electric power supply was already 50% carbon-free, and by 2035 the target is 100%. 

And change is going to come. The government has banned gas boilers from new houses from 2025, and existing gas boilers cannot be replaced after 2035. No technology can take their place at present other than heat pumps. If you’re installing a new gas boiler before the winter, it’s likely to be your last. Better yet, start factfinding on heat pumps. Nothing can slash your carbon footprint as effectively. 

This applies even more if you plan a substantial refurb – adding a heat pump at this stage is more straightforward and will ensure that your beautiful refurbished home is truly future-proof.  The Trust’s guidelines (on their website) may appear daunting. But the reality is that applications are not only rising fast – but the Trust is also taking a constructive approach, and they are being overwhelmingly approved. 

Want to know more? Email reach@hgsra.uk We can connect you to people in the Suburb with a heat pump (and nice warm houses). We are also looking at ways to drive down the costs by using our collective buying power – remember, all 5,000 homes in the Suburb will need a heat pump by 2035. We are looking at street level schemes so installers can create standard installations for similar houses to drive down costs further. Stay tuned for this.

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Article created:16th October 2022