I also watched the same program, and it looked into hydrogen as a possible option and installed it in a street in Whitby against the residents’ wishes. I think that in the coming years, all three systems you described will be applied, sometimes in combination, depending on the type of premises where they can be fitted. Engineers will come up with cost-effective solutions, as they always do. 

Thanks, AMK. That's Whitby, Ellesmere Port - not the better-known fishing town in North Yorkshire. Around ten years ago, Hydrogen was seen as the saviour of the planet. The great thing about heat pumps is that they are effectively around 300% efficient; i.e. the energy required to pump the heat is only about a third of the electrical energy that would be required to be converted into heat energy. Hence to convert electrical energy into hydrogen and then burn that hydrogen does not make economical sense, even before you take into account the additional costs of compressing the hydrogen and transporting it to the points of use. I understand that the experimental scheme at Whitby used hydrogen sourced  from natural gas. This could possibly be a cost-effective process if the hydrogen were to be collected and distributed from that site. Bear in mind however that natural gas is a fossil fuel.

I understand the Whitby scheme is coming to an end but there is a similar scheme in Redcar, North Yorkshire, still progressing. I wish it success but I don't anticipate that it will produce hydrogen in sufficient quantities to be applicable on a large scale, though no doubt it will be usable and economical for some specific purposes.

This could be a whole separate topic - other views most welcome.

Most UK houses aren't fitted with ducting for warm air central heating.  It was briefly popular, but retro-fitting to to existing houses isn't going to be terribly practical.  And air-to-air systems won't heat your hot water tank.

Fitting the house with many smaller air-to-air systems is probably not that hard.  They would be similar to the wall-mounted air con units found in small offices.  But then you get hit by the requirement for planning permission.  The government has allowed a limited permitted development examption for one heat pump per house.  Any more than that, and you need planning permission.  And you will have to show that the noise of all your heat pump units won't affect the neighbours.

Thanks for your thoughts, Simon. I agree - a fanned-absorber unit under nearly window of each house is not going to look attractive. But then we have a similar aesthetic problem right now with solar panels. A group of these making maximum use of the area of a pitched roof has a jagged profile which jars with the roofline. So far there has been little interest in making these in shapes other than rectangular, to blend more pleasantly.

In general. planning authorities are good at coming up (sometimes quite reasonably) with objections, but less good at coming up with ideas of how to improve designs. It is up to engineers to make designs more attractive. A possibility with a self-contained unit could be to try to get as much as possible of the workings inside the house, so  only a couple of air ducts would need to project to the outside of the wall.

I think that in time engineers will come up with improved designs, and overcome some of the technical drawbacks, e.g. limitations on radiator temperature, also bring down costs. If engineers and planners could talk to each other more, that would be a real help.

The other side of this is insulation - if you can keep the heat you spend energy to pump in or out from sneaking back via some other path, this is a large and (once installed), low maintenance  part of the solution. All modern housing, post 1984 will have some sort sort of insulation in all parts of the UK, and in some areas quite a bit prior to that, perhaps as far back as  1967.

The problem is that we have a lot of much older and rather crummy  housing some of which needs a serous upgrade.

One insulation and ventilation controls are properly done, then the choice  of heating  or cooling method is a lot less critical, as whatever you do, there will be a lot less of it needed..

Unpopular though it is, solid wall cladding inside or outside will have a big role to play.

Mike.

Having completed a lot of the required industry and manufacturer training in heat pumps and subsequently realizing the full extent of the work necessary to most existing properties I have come to the realization that heat pumps will only really take off once efficient high flow temperature machines are mass manufactured. I read recently that this technology is being developed with a Scandinavian firm using Helium as the refrigerant allowing flow temperatures of 80c with the same electrical input as todays market models.  

Once these are available as literally plug and play units where by an installer can remove the existing boiler and re-route the flow and return to the exterior heat pump with minimal disruption to the property with no upgrades to the existing radiator system, only then will the great heat pump revolution get underway. Until then it's a false dream.  

Getting 80C output with the same COP as current heat pumps requires something that's pushing very close to a theoretical perfect heat pump.  Our current ones aren't even close to that.

You will always get better efficiency by lowering the output temperature.

I remain to be convinced that conventional heat pumps are the green saviour.  Leaving aside the issue of decarbonisation of the grid, there's the problem of refrigerant loss which has a catastrophically bad green house effect.  I'm troubled at the amounts that get lost from the commercial refrigerant-based systems I manage and until that's solved heat pumps can only be a partial solution.  It might be that better insulation and direct electrical heating provides a cheaper and greener solution.