Heating your home via a direct electrical panel heater or your hot water from an immersion is now lower carbon than using a natural gas boiler. It was 2-3x worse just 8 years ago. There are 2 big issues with direct electrical heating - cost and capacity 2/11
Cost could be largely addressed with agile tariffs [@OVOEnergy @octopus_energy], particularly with smart storage heaters.
Capacity impacts could be reduced by with passivhaus levels of insulation.
But the proposed Future Homes Standard is driving new homes towards #HeatPumps 3/11
Capacity impacts could be reduced by with passivhaus levels of insulation.
But the proposed Future Homes Standard is driving new homes towards #HeatPumps 3/11
So I've run some basic numbers to see what emissions would look like in the future from new homes with gas boiler, air source heat pump (and gas CHP) heating systems to differing insulation and adding 4kWp PV (see assumptions later) 4/11 
This shows some surprising results. Adding PV increases emissions in 2040 & 2050 (as you are saving negative emissions by generating zero emission power - think about it!). Insulating to passivhaus also increases emissions in 2040/2050 as using electrical heat saves carbon! 5/11
Gas CHP (driven by planning to be installed in London on most new developments), was the lowest carbon heating solution in 2013 but is already higher carbon than gas boiler and panel heaters and emissions rise over time. 6/11
Looking at "lifetime emissions", say 15 years for a heating system. Heat pumps come out top and just by fitting a heat pump to a Building Regs house, you could be net carbon negative from now to 2050. 7/11
Looking at cost effectiveness (NB. negative=bad/increasing emissions, low number=good), heat pumps and basic fabric comes out top. So is fitting heat pumps alone the answer in new build? 8/11
I think #heatpumps are key but we also need good actual fabric performance. PV is also unlikely to increase emissions in reality and can help reduce running costs. Agile tariffs show that avoiding evening peaks will also be key so smart controls are also needed. 9/11
So how does this look in retrofit, with higher heat loads? Pretty similar answers from this high level spreadsheet analysis. Hopefully this tread gets people thinking/talking! 10/11
Finally, I am very aware that assumptions drive a lot of these numbers (so here they are). I am also aware a negative grid requires CCS and that hydrogen could replace natural gas (but with massive infrastructure system changes). 11/11
