low energy project advice?

[lbstyling]

Need some expert advice on my home.

I bought it in April. Its a 3 bed semi rendered 1930's house, and is in disrepair.

No heating system was fitted in the property, other than an immersion heater for the shower and taps.


what I have done so far


I put a new roof up over the summer ( inc air tight membrane.) And had planned to do external wall insulation and a MVHR unit with a heating element for the heating, along with keeping the electric immersion heater for hot water that was already fitted.

It seams the external wall insulation is not happening now as I cannot for the level I wanted too under the 'green deal', and funding has also been reduced.

The mvhr system is also looking too problematic to install.

the problem

I bought a power shower and pump, along with a cold water tank to run the bathroom, which are partially fitted.
But I need to rethink the whole heating system, and I'm worried that I will need to take them back out as the best answer will be to install a combi boiler.

What should I do??

The only cheap to run alternative I can think of is a air source heat pump attached to a water tank, by I don't think I can get heating payments back as I have a gas supply to the house.?

 

[SilentDancer]

First before you start ploughing down the route you have described can I ask you to step back and ask the question what are you trying to achieve? Which is more important the lowest cost of energy to heat and provide hot water for your home or minimising CO2 emissions?

If your priority is the first one of low energy cost then a gas boiler will be your best option both in terms of cost of installation and unit energy cost. Electricity is 3 times the cost of gas per kW and the difference will get bigger as gas prices fall and electricity prices remain the same to pay for renewable subsidies.

If you want to reduce CO2 emissions then the best best results would be from a wood boiler. Second best is likely to be gas as electricity (currently) is mainly generated from fossil fuels.

You are taking the right route by looking at improving insulation however you may be better improving it to a lower level that does not require improvements in ventilation. If you decide to go to a higher level of insulation then it is best to stick to passive methods. MVHR can be tricky to get right in an existing property and becomes something else to maintain.

Avoid exhaust air heat pumps unless you are planning to put in a second heat source such as a wood burning stove. Without the secondary heating source you will end up with large bills.
Exhaust air heat pump left families with big bills
Nibe heat pump costing loads to run

 

[bernardgreen]

I bought a power shower and pump, along with a cold water tank to run the bathroom, which are partially fitted.
But I need to rethink the whole heating system, and I'm worried that I will need to take them back out as the best answer will be to install a combi boiler.

Why do you think a combi is the best answer ?

If you are happy to have limited hot water then go for a combi. But if you want to have showers at the same time as someone else in the house is using hot water then look very carefully at the specification of the combi. Can it supply a shower and a hot tap without the temperature and / or flow of hot water to the shower changing.

If you have space for header tank and hot water tank then use a heat only boiler. Heat only boilers are less complicated and thus easier ( cheaper ) to maintain and repair.

 

[ScottishGasMan]

Without hefty amounts of insulation AND the Heat Recovery system, you will really struggle to efficiently run an AirSource heat pump in a house that age, and would still need a gas backup in the winter more than likley.

I'd agree with above and go for a Heat only with a hot water cylinder, easy to maintain, cheapest to run, and would still allow for renewable expansion onto the system if you choose correctly and leave room for future addition.

Out of curiosity as I have played with the idea of a whole house heat recovery unit also, whats the problem with getting it installed?

 

[SilentDancer]

Out of curiosity as I have played with the idea of a whole house heat recovery unit also, whats the problem with getting it installed?

The problem is installing the ductwork. It has to be quite carefully planned to ensure it works effectively and then there is the upheaval to ceilings to get it in place. On an existing property I'd say it was only sensible if you've got plans for a major refurbishment.

 

[Dan Robinson]

If you have space for header tank and hot water tank then use a heat only boiler. Heat only boilers are less complicated and thus easier ( cheaper ) to maintain and repair.

Twaddle.

 

[Gasguru]

And so the Intergas promotion begins.....

 

[Dan Robinson]

Maybe later.

But point of fact a combi (non Intergas) is just a flirking W-Plan with a plate instead of cylinder.



Now an Intergas on the other hand.......

 

[Norcon]

Need some expert advice on my home.

I bought it in April. Its a 3 bed semi rendered 1930's house, and is in disrepair.

No heating system was fitted in the property, other than an immersion heater for the shower and taps.


what I have done so far


I put a new roof up over the summer ( inc air tight membrane.) And had planned to do external wall insulation and a MVHR unit with a heating element for the heating, along with keeping the electric immersion heater for hot water that was already fitted.

It seams the external wall insulation is not happening now as I cannot for the level I wanted too under the 'green deal', and funding has also been reduced.

The mvhr system is also looking too problematic to install.

the problem

I bought a power shower and pump, along with a cold water tank to run the bathroom, which are partially fitted.
But I need to rethink the whole heating system, and I'm worried that I will need to take them back out as the best answer will be to install a combi boiler.

What should I do??

The only cheap to run alternative I can think of is a air source heat pump attached to a water tank, by I don't think I can get heating payments back as I have a gas supply to the house.?

Definately stay clear of combi's if you have space for cylinders.
With a cylinder you have future proofed the property for solar energy.
It's a no brainer.

 

[Dan Robinson]

Are you saying a Combi can't be run on Solar Nobby?

tut tut.

A combi isn't future proofing? Crap!

A combi could be argued to be the ultimate in Future proofing as it can remain a combi and still feed a cylinder and be connected to solar as well as be connected to a solar cylinder.

The instant water side can be tasked for minor draws to help preserve the solar store until larger volumes needed for baths and showers.


Of course, you don't even need to use the combi as a combi if you wish. Installed plenty where a new boiler was needed but final plan for property wasn't in place so to save changing a boiler twice, a slightly more expensive boiler was fitted at the risk of not utilising its full potential.

 

[Norcon]

The only thing a combi future proofs is parts changers with vested interests.

 

[Dan Robinson]

More twaddle.

 

[lbstyling]

Hi all,

Yes the MVHR was the original plan, combined with a small air source heat pump or basic electric 2 kW heating element that is inside or fed into the MVHR system for distribution around the house.

This could be installed by myself , and would have freed up the funds for further insulation via EWI.

The MVHR systems efficiency and noise level is dependant on the diameter of the pipework that goes into and out of the system. 5" minimum. 6 -8 " ideal.

These pipes would need to go from the unit to the kitchen, bathroom, living room bedroom 1 and 2 go outside. I would hardly have any beams left in the house that were structurally sound after drilling a min size of 60mm x 205 mm oval holes for each.

The log burner is the real killer though. The burner needs to draw air into the room,but it seams that a mvhr will not redistribute heat in a house as air is an inefficient transport of heat, and the flow will always be towards the burner anyway due to combustion.

The only solution to this would be a back boiler for my log burner which themvhr could draw heat off the rad in another room.

This would still leave me with an electric immersion foathe taps and shower, which seams all wrong.

This leads me back to a combi, at the cost of some of the insulation, and single room heat recovery units in the bathroom and kitchen.

The problem with all this is it seams very little installation cost difference between a massive 40kw or whatever combi system and the 12kw for a shower that I would need.

 

[Norcon]

If you have a two storey dwelling then a boiler stove isn't a bad option.
Set up correctly and you have two rooms heated, hot water and no need for electricity.

Thats how mines set up. No need to go overboard. 8kw to water is ample. It the most trust worthy and reliable system you'll ever install.

 

[lbstyling]

OK, think I have the solution.....

Basically, fit a back boiler to my log burner. (Thanks norcon)

A solar thermal panel or 2.

And keep the immersion element and tank, but my tank would have to be replaced with a multi tap one.

The back boiler heats the tank for winter ( as it will be on in winter anyway)
The solar heats for summer ( as sun is only about in summer)
And the immersion only kick in when the others arnt enough!

Problems to figure out-

safety system needed for linking the log burner to the tank (boiling water risk/ explosion?)

How to make immersion heater automatically kick in at 6am if the water temp isn't high enough, and turn off once hot enough or after 8am.

Never heard of anyone with a system like this, but I know its possible -see here-

http://www.boilerstoves.co.uk/linked-systems.html

And one more thing to figure out -assuming reasonable insulation is used, can both a ground and first floor house be heated enough from just underfloor heating on the ground floor?