Should I switch to Infrared radiators or install TRVS?

[NJneedshelp]

Hi!

We're looking for advice for our 1905 built (renovated in 2010) victorian house for the future of our heating system. The house is 2 floors and runs 2 different systems and hot water.

On the ground floor we have water based underfloor heating with a mix of tile and wood floors with each room having their own thermostat. On the first floor we have a series of 5+1(towel rack) aluminium and steel radiators, hooked up to a Nest thermostat in the hallway, as all of them still have a manual valve (so no zoning possible at the moment). The system has 2 valves: Heating and Hot Water, so if the heating downstairs comes on in a single zone, the upstairs heating does as well.
The gas boiler and the unvented-cylinder are also on the first floor.

The house is currently D-rated in energy efficiency and needs some insulation work as part of this project.

We were thinking either replacing the upstairs radiators with infrared electric ones and continuing running the bottom system and hot water on gas, potentially moving to a air heath pump or a fully electric boiler for UFH and Hot Water down the line.

Am I mad to think this, or should I just have the existing radiators be installed with TRVs instead?
With 5 new radiators (I guess the towel rack will be just a non-heated one if we remove the central heating from the upstairs room), and work needed to remove the old system (leaving the pipes in the floors, but removing the connection to the boiler), I'm projecting a ball park figure of ~£5k, is that realistic?

Thanks so much for any tips and help - haven't been able to get good advice from reaching out to plumbers and I don't know who to consult on this.

 

[JohnD]

Am I mad to think this

Yes

Electricity costs four times as much as gas.

 

[JohnD]

our 1905 built victorian house

Edwardian.

 

[ericmark]

Since electric costs more than gas, I would not use infrared heating on it's own, however using gas back ground heating and infrared heating on using the room has been done for years, we called it the tungsten light bulb.

What we are looking for is speed, which is why in the main under floor heating does not work, in the main we don't use all rooms 24/7, if we did UFH would be good, but in my case, retired, so at 11 pm I stop using all but bedroom landing and bathroom, and the latter two for a very short time, at around 8 am I will use the kitchen again for a short time, and then the living room, the living room will be used all day until 11 pm, but around 6:30 pm will use kitchen, and 7 pm the dinning room, well to save energy in winter eat in living room so dinning room not heated.

So I set the TRV's in each room to turn on only when required only cheap ones, cost me £15 each for heads in 2019, the main problem is I use oil, with gas the boilers modulate, so as long as it is running, the TRV's can control each room, but with oil to get the boiler to run, the main wall thermostat is set to reduce by 0.5ºC an hour before room required, then back up 0.5ºC when required, so the boiler runs when TRV's change temperature.

There are now some very clever TRV's, the Drayton Wiser is claimed to work out how long it takes to heat the room, so you as user set when you want to use the room, and it works out when to switch on so room is up to temperature when you want to use it. But their TRV heads cost a lot more than £15 each.

The Myson iVector fan assisted radiator can heat an maintain rooms temperatures very quickly, it has 5 fan speeds and it adjusts speed of fan to heat or maintain room temperature, but the cost of the radiators and the building management to control them, means not really suitable for domestic buildings, they are used in commercial buildings as same unit can both heat and cool, but then looking at heat pumps, not simple central heating boiler.

So we are looking at a compromise, near enough engineering, to get it A1 costs too much, but much is down to room use and heat loss, if heat loss is very low, then under floor heating may work, but as the heat loss increases then we want to only heat when required.

So we start to look at back ground temperatures and the temperature when room is in use, often called eco and comfort, if you allow a room to cool to 10ºC it will take some time to reheat to 18ºC which the international health organisation say is comfortable, although personally I would go for 20ºC, but if we hold the room at 15ºC then reheat time is reduced, I tend to go for 17ºC as Eco and 20ºC as comfort, but that's up to you.

So if one keeps the bathroom at 17ºC and have a infrared heater on a PIR as you walk in, then that will reduce losses compared with holding at 20ºC all day, so we are looking for in many cases a mixture, but the energy rating does not take into account control.

I fitted UFH (electric) to mothers wet room, step one was bandjack out the floor, lay drains and then insulation around 9" as had to go down for drains, the floor felt so nice and warm, but on switching off the heating, it still felt nice and warm, all down to insulation not the UFH. The UFH was really a failure, as it needed switching on 2 hours before use, if not more, so to heat the room for a shower taking 10 minutes needed heating on for 3 hours, clearly not cost effective.

But down to room use, can you predict when room will be required?

 

[bernardgreen]

Since electric costs more than gas, I would not use infrared heating on it's own, however using gas back ground heating and infrared heating on using the room has been done for years, we called it the tungsten light bulb.

Well said.

The heat radiating from a tungsten lamp in a chilly room is a source of comfort,

 

[robinbanks]

we called it the tungsten light bulb.

But, it's 100W - a dedicated heater is going to be ten times that at least, and it won't be run for a tenth of the time

Gonna need some major insulation and draught proofing upgrades to have a 100W heater make a dent in the kinds of rooms we're discussing here?

 

[ericmark]

Rooms need 10 to 80 lumen per square foot, so my living room, 22 x 16 needs between 2 minimum to around 10 bulbs, as 50 watt down lights more like 16, this would be 800 watt, of which around 100 used for light, and not talking about fully heating the room with the lights, although that's what was done with this building the MANWEB headquarters in Chester but just allow the back ground temperature to be lowered, so ventilation will cost less, use of heat recovery units may reduce the cost of ventilation, but we can't simply spray expanding foam into all the air bricks, although often that is what happens with cavity wall insulation.

However what I am saying is one can use a mixture to heating methods, I have these TRV's and the left button changes it from Eco to Comfort and back, so as one walks into the room you can press the button to increase the temperature, but it takes time to lift the room by 2ºC, where the infrared is nearly instant, but much depends on the life style of the people living in the home, with retired people it is likely under floor heating would work, specially where no gas or oil, so need to use heat pumps, but where the occupants are at work all day, it would only work to give a back ground heat, you want to allow the home to cool while not occupied.

I personally with global warming would say a heat pump needs fan assisted radiators so it can be used to heat and cool, but the cost of Myson Ivector fan assisted radiators is rather high, but likely less than UFH, but once you use a fan, you know when the heating has turned off, and one is tempted to turn heating up a bit.

I used the old Myson fan assisted, and they did work well, again looking at speed to reheat, I could walk into a cold house, turn on the central heating and 4.5 kW gas fire in living room, and with a 4 kW normal radiator and a 3.5 kW fan assisted radiator within ½ an hour the room was toasty warm and I was turning down then off the gas fire. Where in this house to heat the living room when coming home I would need geofencing. The 20 kW boiler will maintain the house, but to heat from cold it's slow.

There is no heating system which will suit all homes and all life styles, OK my brother-in-laws old house had multi-fuel, the log burner, solar panels, LPG boiler, and electric all fed into a pair of water filled cylinders which would hold enough to reheat the house, so when visiting children in Germany the solar panels would stop home freezing while he was away, and have enough to reheat house on his return, and using local wood when home the running costs was down to petrol used in chain saw, however the system cost £12,000 to install, takes a lot of years to pay that back.