New build - heat and energy considerations

[Tyke2]

I fancy wet UFH downstairs, but radiators upstairs. Im not sure how easy this is as they would run at different water temps. If i go with Solar thermal too it gets more complicated. Id probably use someone with expertise to design a system and work with someone local to install it. But if the instal cost is prohibitive I'll go standard gas combi with thermal store as i have now.

 

[Hecateh]

4 minutes ago, Tyke2 said:

I fancy wet UFH downstairs, but radiators upstairs. Im not sure how easy this is as they would run at different water temps. If i go with Solar thermal too it gets more complicated. Id probably use someone with expertise to design a system and work with someone local to install it. But if the instal cost is prohibitive I'll go standard gas combi with thermal store as i have now.

 

Mine is split level and I have 2 floors of wet and upstairs electric ufh and towel rail in the ensuite and dressing room.  I like sleeping in the cold so haven't really planned much for the bedroom.  I can easily add some electric if I need to in the future.  I am pretty sure it will be kept from getting too chilly from the rising heat

[newhome]

1 hour ago, Tyke2 said:

But if the instal cost is prohibitive I'll go standard gas combi with thermal store as i have now.

 

If I had gas I wouldn't even consider solar thermal TBH. 

[Nickfromwales]

3 hours ago, Tyke2 said:

Hi I will come and have a look if thats ok.

Im as much interested in the next stage also. I.e how it all plumbs in together. UFH,Thermal store, radaitors ands perhaps Solar.

The issues I have on work installs are that each technology is fine on its own, but getting them to work together is more difficult.

The key is to build as low energy as possible and to go for all low temp emitters where possible. 

Rads, unless seriously oversized, will make an ASHP uneconomical to run. Try and get low grade space heating and then an ASHP makes much better long term sense. 

Avoid gas and oil where practicable, and get PV into the equation as the cherry on the cake. Possible ratio of 1kW inputted ( some from PV ) per 3kW produced ( via the HP ) makes the best sense. Having a chunky slab as a ‘storage heater’ will allow you to store in the day and emit during the night eg where you need to bridge the gaps where there is no solar gain / reduced outside temps. 

TS’s are notorious for excessive heat loss ( latent ) so avoid wherever possible. 

Edited September 10, 2018 by Nickfromwales
inputted

[Tyke2]

16 minutes ago, Nickfromwales said:

The key is to build as low energy as possible and to go for all low temp emitters where possible. 

Rads, unless seriously oversized, will make an ASHP uneconomical to run. Try and get low grade space heating and then an ASHP makes much better long term sense. 

Avoid gas and oil where practicable, and get PV into the equation as the cherry on the cake. Possible ratio of 1kW produced ( some from PV ) per 3kW produced ( via the HP ) makes the best sense. Having a chinky slab as a ‘storage heater’ will allow you to store in the day and emit during the night eg where you need to bridge the gaps where there is no solar gain / reduced outside temps. 

TS’s are notorious for excessive heat loss ( latent ) so avoid wherever possible. 

Thanks. Its all quite overwhelming!

Ideally I would have UFH downstairs. Radiators upstairs ( Mrs T wants to dry her washing). These are the basics of what I would like.

As there is no gas in the village I assumed I would need either Gas or Oil tank installed.

So what are the options on a pretty standard construction, 250m2 house, traditional build, concrete ground floor slab.?

Ideally as little that is mechanical as possible. In my experience the more hitech "green " stuff I have in the buildings I'm involved in through work, the higher the running and maintenance costs.

Also I want to have heat on demand. Again shivering at night is not on the agenda.

[Nickfromwales]

A HP will tick all those boxes, but you really need to adopt a ‘fabric first’ approach if you want to steer away from fossil fuel. High fabric & ventilation heat losses will not lend itself to low grade space heating so that may well end your chance of having UFH tbh. If you need X amount of W/ m2 and it exceeds what UFH can safely / economically provide then your back to radiators both up AND downstairs.

Cooking on gas is still feasible with LPG bottled gas, in case that’s a concern / requirement. 

Sorry that I haven’t followed much of your other content, but how far along are you ?

 

[Onoff]

You only pay for insulation ONCE. Payment for "fuel" in whatever form is ongoing...forever.

[PeterW]

50 minutes ago, Tyke2 said:

So what are the options on a pretty standard construction, 250m2 house, traditional build, concrete ground floor slab.?

 

Just down the road if you want a look..?

 

160sqm room in roof. Brick skin, 150mm blown bead, medium block and 25mm insulation to certain rooms. UFH in concrete slab. 

 

As for drying washing, stick a drying rack in the utility below the MVHR extract and it will work perfectly. 

[Tyke2]

So - Im at the stage of trying to agree a plot purchase, so quite premature to be worrying about heating some may think.

But say I want UFH and this effects the floor slab design/thickness. So it needs thinking about SAP I think. Similarly the plot is in a conservation area and at present would need a natural stone roof. So If I want PV there is some work to do.

I'm a fan of "fabric first" but not a fan of lots of mechanical gadgetry. I'm happy to be educated, but MVHR, HP etc seem to be ringing my maintenance alarm bells.

In back ground for a living I manage a company that manages a large portfolio of big public buildings. The ones built in 2004 to 2008 have traditional heating systems and opening windows. Their energy consumption is £x. The buildings built late on to Breeam standards with PV, HP, MVHR, ST are generally running at £x +40%. So you can understand why I'm sceptical.

[Ferdinand]

2 hours ago, Tyke2 said:

Thanks. Its all quite overwhelming!

Ideally I would have UFH downstairs. Radiators upstairs ( Mrs T wants to dry her washing). These are the basics of what I would like.

As there is no gas in the village I assumed I would need either Gas or Oil tank installed.

So what are the options on a pretty standard construction, 250m2 house, traditional build, concrete ground floor slab.?

Ideally as little that is mechanical as possible. In my experience the more hitech "green " stuff I have in the buildings I'm involved in through work, the higher the running and maintenance costs.

Also I want to have heat on demand. Again shivering at night is not on the agenda.

 

Another axiom is Simplify ! Simplify ! Simplify !

 

I would not call it consensus, but some of us find that simpler central heating controls are appropriate in a more highly insulated house.

 

If your whole house is so well insulated that you need minimal heating (say approaching passive), then it is more practical to keep it all warm and not have say 8 roomstats, the wiring and the fitting expenses. The financial balance of loads of gubbins vs the lifecycle saving that results can be modelled.

 

Another example is to have no major heating upstairs in the same circs (and either put some minimal preparatory plumbing or wiring in, with nothing attacked or accept that you will have some sort of portable elecric heater as a backup just in case your calcs were optimistic.

 

There are various strategies.

Ferdinand

 

[Nickfromwales]

1 hour ago, Tyke2 said:

In back ground for a living I manage a company that manages a large portfolio of big public buildings. The ones built in 2004 to 2008 have traditional heating systems and opening windows. Their energy consumption is £x. The buildings built late on to Breeam standards with PV, HP, MVHR, ST are generally running at £x +40%. So you can understand why I'm sceptical.

I bet none of them were designed with a true scrutinising eye, and few are maintained accordingly. Also, the shear size of the maintenance should be accounted for in the very nature of them being commercial properties, eg the £X + 40% should be factored in as running costs / consumables and would have been calculated and 'factored in'.

If they've ended up so wonky as to be +40% then someone got it all wrong  Lets compare apples with apples, and theres enough real life data on this forum for you to see that you need not worry about going +40% at all, unless you choose not to heed and observe the disciplines adopted and religiously followed by the many who have self built here ( and have been kind enough to share the results ( warts n all )). Plus your building a single residential dwelling under your own supervision so are in charge of your own destiny there  

[Onoff]

1 hour ago, Tyke2 said:

The buildings built late on to Breeam standards with PV, HP, MVHR, ST are generally running at £x +40%. So you can understand why I'm sceptical.

 

Is that because the maintenance providers charge a premium for looking after "new fangled" stuff?

[Nickfromwales]

Just now, Onoff said:

 

Is that because the maintenance providers charge a premium for looking after "new fangled" stuff?

Yup. Its called money for old rope. 

[ProDave]

I think commercial buildings are a poor example.  Certainly my experience is occupants don't give a flying fig about energy conservation.  When was the last time you saw an office worker turn off the lights, even on the brightest sunny day?  If it's too hot, open a window, but leave the heating on. I knew plenty of people that kept a fan heater under their desk, if the set 20 degrees was too cold for them, they put their heater on, they are not interested in the bill.

[Tyke2]

15 minutes ago, Onoff said:

 

Is that because the maintenance providers charge a premium for looking after "new fangled" stuff?

No I am talking of energy costs only. I think maintenance cost of a ASHP would be similar to a boiler etc though.

[Tyke2]

8 minutes ago, ProDave said:

I think commercial buildings are a poor example.  Certainly my experience is occupants don't give a flying fig about energy conservation.  When was the last time you saw an office worker turn off the lights, even on the brightest sunny day?  If it's too hot, open a window, but leave the heating on. I knew plenty of people that kept a fan heater under their desk, if the set 20 degrees was too cold for them, they put their heater on, they are not interested in the bill.

The buildings are sealed. I.e no opening windows.. Lights are PIR. Heating level set centrally with no local control.

[newhome]

24 minutes ago, Nickfromwales said:

Yup. Its called money for old rope. 

 

AKA daylight robbery! 

[newhome]

15 minutes ago, ProDave said:

When was the last time you saw an office worker turn off the lights, even on the brightest sunny day?  If it's too hot, open a window, but leave the heating on. I knew plenty of people that kept a fan heater under their desk, if the set 20 degrees was too cold for them, they put their heater on, they are not interested in the bill.

 

Here the lights go off if no movement, sometimes when I’m working so clearly no sign of life lol. No opening windows just aircon. No fan heaters allowed. Fans are only allowed as a special order if you’re pregnant or menopausal - yes really! ? 

 

 

[Tyke2]

21 minutes ago, Nickfromwales said:

I bet none of them were designed with a true scrutinising eye, and few are maintained accordingly. Also, the shear size of the maintenance should be accounted for in the very nature of them being commercial properties, eg the £X + 40% should be factored in as running costs / consumables and would have been calculated and 'factored in'.

If they've ended up so wonky as to be +40% then someone got it all wrong  Lets compare apples with apples, and theres enough real life data on this forum for you to see that you need not worry about going +40% at all, unless you choose not to heed and observe the disciplines adopted and religiously followed by the many who have self built here ( and have been kind enough to share the results ( warts n all )). Plus your building a single residential dwelling under your own supervision so are in charge of your own destiny there  

The buildings are all designed by an M&E/building services specialist engineer, with accompanying Breeam assessor. All are maintained in accordance with manufacturers and design requirements, and audited on a quarterly basis. There are "energy committees" in the buildings to engender good practices with staff.. i.e no fan heaters, close doors to corridors etc.

It is definitely not apples with apples as you say. But the data is very robust.

[Nickfromwales]

1 hour ago, Tyke2 said:

No I am talking of energy costs only. I think maintenance cost of a ASHP would be similar to a boiler etc though.

Not really, as there are far more moving / electromechanical components in a combi. 

[ProDave]

I am not aware of anything in my ASHP to "maintain" or "service"  I am sure it's a case of use it until it breaks then repair (or replace) it.

 

You might think the fan bearings might need greasing, but no mention in the manual.

[Onoff]

1 hour ago, Tyke2 said:

The buildings are all designed by an M&E/building services specialist engineer, with accompanying Breeam assessor. All are maintained in accordance with manufacturers and design requirements, and audited on a quarterly basis. There are "energy committees" in the buildings to engender good practices with staff.. i.e no fan heaters, close doors to corridors etc.

It is definitely not apples with apples as you say. But the data is very robust.

 

Are you a youngster still full of hope and believing in the system?   

 

It's all done to the lowest spec under the guise of "value engineering"! 

 

I dare you to bring up the energy costs of convening and attending the eco cost saving meetings! 

[Jeremy Harris]

Nothing to service in my ASHP.  Only recommendation is that it be inspected annually and the evaporator coil and fan be cleaned, if needed.  Easy DIY job with no safety issues (other than turning the power off before you clean it).

[Guest Alphonsox]

There's nothing to say you need a ASHP, both @TerryE and I are running our UFH systems from 3Kw immersion heaters (aka Willis heaters). This strips space heating down to its bare minimum of a thermostat, a pump, a few runs of pipe and a heating element - Can't get much simpler without going all electric. (And I speak as someone who has a couple of unused ASHPs in the garage).

[Tyke2]

53 minutes ago, Alphonsox said:

There's nothing to say you need a ASHP, both @TerryE and I are running our UFH systems from 3Kw immersion heaters (aka Willis heaters). This strips space heating down to its bare minimum of a thermostat, a pump, a few runs of pipe and a heating element - Can't get much simpler without going all electric. (And I speak as someone who has a couple of unused ASHPs in the garage).

That's interesting. What's the annual running cost of running?

Also what's the domestic hot water situation ?  Temp/ flow etc?

Why have the ASHPs and not fit them?

Ill take a long look at the heating threads to swot up a bit,