I'm not keen on them either. In my last job we had storage heaters on two floors and the bills were astronomical however, many landlords have little wiggle room when it comes to choice of heating systems. If you rent a flat out in a block of flats then you cannot insulate outer walls and most blocks do not allow gas. Alternative sources of "greener" energy don't really apply either so you're left with storage heaters, panel heaters or liquid filled radiators. Narrowing the options even further we have the problem of the EPC assessor having clear preferences over storage heaters and penalising any other form.
It is not the assessors preference, it is purely down to the cost of running the heating system. Energy Performance Certificates only considers the cost of heating and lighting, it does not consider the potential Global Warming effects, the preferred choice always has been and still is a gas fired boiler for space and water heating in properties like this flat.
Since the thread started, I have talked to my daughter who remembered to flat she lived in post code, so I had a look, and rated D, how? No double glazing and a D? But looking at my own house it says "Secondary heating Room heaters, dual fuel (mineral and wood) N/A" Now I thought N/A means not any? But I have an open grate. But it seems down to a point system, so many points for double glazing, so many for cavity wall insulation, so many for loft, and a lot of assumes, and the rating for having TRV's is the same as having programmable TRV's which can be used to turn off the heating in rooms not in use, so the Energy Performance Certificate is in real terms useless. I look at Celoxtex insulation board with says "Excellent thermal performance with a thermal conductivity of 0.022 W/m.K, reducing the thickness of insulation required to hit the target U-value." If the report used thermal images then yes it would show real energy efficiency, however the report could only be done in the winter months, and it would need compensating to cater for different room temperatures. But again location, driving back from shopping yesterday I saw the smoke raising from a house chimney, could be aga I suppose, but more likely due to being in a valley and getting little sun shine, same for homes across the valley to me, they get much less sun shine to me, and those further up the hill get a lot more. However in the 60's before central heating the fire was never lit before 5 pm, during the day we did not heat the house except for the aga, and in the mornings lovely pattens on the windows where the moisture had frozen, I was told it was done by some one called Jack Frost. It didn't cost us more back then to heat the home, we simply did not heat it.