Steven Heath, Technical Director for Knauf Insulation, Northern Europe, looks at the likely objectives of the upcoming Warm Homes Plan.
The Warm Homes Plan is promised in spring and the objectives can be guessed:
- home interventions that deliver warm, affordable-to-run homes;
- bills must not go up if moving a home to low-carbon heating (ideally, they go down or it’s not really a warmer home);
- more accurate & reliable EPCs to support household decision making.
All great outcomes. But no-one in government owns these outcomes or the consequences if not delivered. Retrofit & newbuild policy stops at installing ‘things’; fingers are then crossed that an imperfect policing regime will deliver a high performing install. This goes for insulation and heating measures. Most risk of poor delivery sits with occupants. The Warm Homes Plan can address this.
The holy trinity of affordable home heating is in figure 1. The red bar represents annual heat demand to achieve a set temperature in an average weather year – the lower the number the more efficient the home. The green bar represents heating system efficiency – the higher the figure the more heat per unit of energy (key for heat pumps). The blue bar represents the average unit price paid for electricity (if heating with a heat pump) – a function of tariff, home heating flexibility (can you heat at cheap times of day) amongst other elements.
Figure 1 – Low annual heat demand (kWh), efficient heat pump (sCOP), competitive tariff
If this shows what ‘good’ looks like, what’s ‘bad’?
Figure 2 – High annual heat demand (kWh), inefficient heat pump (sCOP), uncompetitive tariff
Deliver a poorly installed heat pump in an inefficient home (perhaps where the assessment / EPC fails to capture a home efficiency performance gap) to a family less able to shift their heat demand (i.e. not the tariff-savvy, gadget-rich teslaratti) and we might get the nightmare scenario above.
And here is the crux – fail to measure the red & green bar for each home and it’s all guess work where home, or heating system, efficiency land. Some insulation and heat pumps will be installed well, some won’t. And it’s not just existing homes. We are measuring fabric efficiency (Heat Transfer Coefficient) in a series of case study homes – newbuild and old – and replacing the loft insulation with a high-quality install (measuring pre and post). We didn’t search out poor installs…we didn’t have to (my house amongst them). We found one home with a new way of getting loft insulation wrong – a nice blanket of insulation sitting on top of boarding (serving no obvious purpose) with no insulation below boards, between joists.
To explain to the resident the concept of thermal bypass, we created the image of sleeping under a floating duvet. A colleague’s view was more direct – “you may as well hang the insulation on the garden fence”. The occupants already knew their newbuild home was cold.
A key pillar in the Warm Homes Plan will be a newly designed ECO. Officials suggest the policy will be about occupant choice: occupants can choose between different insulation measures and heat pumps. Put frankly, that’s a rubbish choice. Can they not choose a home with measured low heat demand or a proven high heating system efficiency? That’s the choice I want.
All policy to date has focused on ‘things installed’. The promised outcome is assumed. A tick-box exercise that does nothing to reward good practice. A Warm Homes Plan that does the same will repeat the errors of the past. Measurement – SMETERs of fabric and sCOP for heat pumps – is a large part of the answer. HeatpumpMonitor.org is paving the way in transparent performance measurement for heat pumps. This is the choice I’d like. I’ll have a heat pump if I can choose from the top performing installers / heat pumps and a promise to measure my install …and fix it if it’s underperforming.
Immodestly, Knauf is paving the way in fabric efficiency measurement. Accurate, accredited and audited fabric measurement technologies (SMETERs) can do for fabric what HeatpumpMonitor.org can do for heat pumps (if both are driven by policy). Measured outcomes on both red and green bars need to be central to the Warm Homes Plan if we are to persuade households to act. Sensing is everywhere in the modern world; why wouldn’t we deploy sensors to tell us if a Warm Homes Plan really is delivering warm homes?
Steven Heath is talking about delivering retrofit at InstallerSHOW which is 24 to 26 June at the NEC. Register for your FREE ticket here – parking is free, too.
