Bloody tired of being confused. What heating system to fit ?

[Big Jimbo]

So in spring i will be starting the build of my first house. I have permission for two however, as i am going to have to borrow money commercially, (no income) . I will have to build and sell the first house, in order to provide the funds to build the second house for me to live in.

Now i want to build a decent house, but not go over the top on spending as it will be sold.  The house will be 1750square foot, 4bedroom, three bathroom. The ground floor is 94 square meters, and i intend fitting underfloor heating. The upstairs is 74 square meters and i intend fitting radiators. A water storage tank of 250 to 300l will be fitted to provide hot water. I have sized this to give the chance to have three 10min showers at the same time, with the water being stored at 45c.

There will be One kitchen sink, One WC sink downstairs. Two of the bathrooms will be above the water tank, and the other will require a pipe run of about 10meters.

The upstairs rads will be run from a manifold upstairs. I have done this in the passed twice with home made manifolds and it has worked well.

The downstairs underfloor heating will be run from a manifold. I have as yet no idea re zones etc, but basically i will have a front sitting room, that i anticipate will be used mostly in the evening. a largish entrance hall. WC. Small laundry room. Study (where the hot water tank will be) and a large kitchen, dining family area.

I have completed, what i believe to be a comprehensive heat loss calculation, and my result is a 5kw heat need. That was worked to 21 degrees inside, and -4 outside. I have even compensated for altitude, 150meters above Heathrow Airport. I have designed to an airleak score of 5, but hope to get nearer to 3.

Obviously as a new build i have decent "U" values, and so a heat demand of 5kw seems decent ? I have been told that a 6kw heat pump would be fine, as long as i make sure i get One that can modulate down nice and low. I have been told that a gov grant of £7.5k is available via getting the kit i would need from a registered supplier ?

Although i have gas on site, i'm keen to think about an ASHP. One of the reasons is that i have room on the roof for Aprox 10 solar panels South facing, And 10 West facing. I intend fitting these during the build while the scaffolding etc is up. I don't have the budget for fitting any battery storage, but intend getting the various wires run while the house is being built, so that they can be fitted with very little hassle in the future if wanted. I also have to fit an EV charger, although i dont have an electric car.

 

Can anybody give me a bit of a steer if the above sounds ok? The biggest hold back i have is the internet being filled with people moaning about how ther heat pumps are rubbish. A local new estate has been built with heat pumps, and the moaning about cost, and lack of heat is all you hear from the people.....

To top it off, i spoke to a heating engineer, who is actually a friend of that bloke Adam, from heat geak, and he said size everything for low temp running, make the install Heat pump ready, and stick a bloody gas boiler on the wall !!!!!!!!

Any steer would be gratefully received.

Regards Confused (Tired of being) and with far too many other things to get on with.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[JohnMo]

28 minutes ago, Big Jimbo said:

ground floor is 94 square meters,

So assume about 188m² (can't be arsed converting ft²) so 5kW sounds high. Would have expected 3 to 4kW.

 

You can go grant, but by the time you're adding the MCS markup you will paying out as well. 

 

PV just couple to a 2x mppt string inverter. At a later date this could have an AC coupled battery added without touching much on the solar side. Or hybrid would replace the inverter.

 

A 6kW Hiaer heat pump is £2100 including vat and you need to add a wiring center and controller for £550 Inc vat. It will modulate down to 1.6kW. (the 4kW down to just under 1kW)

 

Sling in a direct UVC and run DHW from immersion (off peak), heat to 60 degs and install a smaller cylinder. Run UFH and radiators at same temperature, all one zone. Simple install, minimum materials, cheapest to run.

44 minutes ago, Big Jimbo said:

spoke to a heating engineer

Makes wonder - I would just ignore him and don't get him anywhere near your install.

 

Don't bother with the grant, not worth the hassle and fighting over someone saying you need a 10 to 12kW ASHP.

[Big Jimbo]

@JohnMo Thanks for your imput. I was hoping you would chip in. The total size is 1750 square foot.  I believe i was dilligent when doing the heat loss calcs, but im happy to re-visit them.  As for the other stuff you have stated, i will do some reading up. I'm afraid i'm a very practical guy, rather than an intelect. Old cars i can play with the mechanicals, and usually get things sorted. New cars with all the electronics. Not a chance.

The main problem is having confidence in trusting someone else to design the system up, and unfortunately my previous expierience has not been great. I wouldn't even mind paying someone to design and pipe size etc. Just want to make sure i'm doing the best that i can

Thanks again.

[Big Jimbo]

With regards the heat loss calcs, i am only doing roof and wall to current building regs, with block and beam floor and tripple glazed windows being slightly better. I do have a fair few windows, and my part "O" was a bit task to get a pass on the simplified version.

[JohnMo]

Pipe sizes are simple for a heat load of say 5-6kW, I would just run 28mm until pipe splits for downstairs and upstairs then 22mm to each manifold. UFH pipes 16mm, and rads from manifold 15mm

Edited 6 hours ago by JohnMo

[JohnMo]

The installation I am talking is simple. You will need a room by room heat loss calculation, then size emitters to room heat loss at same flow temperature.

 

Direct cylinder with immersion timer. Set timer to any low tariff periods.

 

ASHP, outside unit power cable via isolator switch. Two core screened cable between outside and wiring center. Power to wiring centre. Controller within wiring centre. No room stats. That's it no need for 2 port or 3 port valves.

[Big Jimbo]

Thanks @JohnMo That's much more in my language. Thank you.

[Mr Punter]

So the first house you build is a spec development.  Buyers will not be very interested in the heating system, EPC score or airtightness, just location, what it looks like, number of bedrooms and price.

 

People are used to gas boiler and rads, so unless ASHP and UFH are cheaper, think twice.

 

You will need a design stage SAP NOW!  This will inform the minimum level insulation, heating system, hot water and airtightness needed for you to get Building Regs.  Do it for as little money as possible.

[SimonD]

1 hour ago, Big Jimbo said:

The biggest hold back i have is the internet being filled with people moaning about how ther heat pumps are rubbish. A local new estate has been built with heat pumps, and the moaning about cost, and lack of heat is all you hear from the people.....

 

That's because the design, installation and commissioning is shite, not because heat pumps don't work. Unfortunately, you only really hear about the bad stuff, and the made up nonsense about how they don't work.

 

I recently did the design and installation at an old house where half of it has 600mm uninsulated stone walls and the other half okay insulation badly detailed. They were having a load of renovation work being done and when the owner was telling the trades including plumbers I was coming to fit a heat pump, they were all negative saying it would never work bla bla. Did the install and the trades came back to do the finishing work and never stopped commenting on how warm the house was..... the owner is delighted saying the house has never been so comfortable.

 

I know I'm blowing my own trumpet but there are plenty of genuine good installers out there that do a proper job and leave their customers very happy. 

 

However, I understand your worries. I'm here now as a designer and installer of heat pumps because I couldn't find anyone I could trust to do the design and install in our house. I first went down the route of installing a gas boiler myself and have just swapped this out for a heat pump. I have to say, the heat pump is just so much better by a mile.

 

With your calcuated heat loss you can have something very simple, as @JohnMo says, and it can be very efficient.

 

Now, I know that the BUS Grant is a prickly thing here on BH, but the idea that this just leads to price gouging by installer is IMHO, just nonsense. People need to properly run through the figures to understand why this is nonsense. For example, in the job above, the materials list for the whole job came in at more than £11k ex VAT without any uplift for me. If you're getting someone in to do the whole design and installation, the extra £7500 is something worth having as long as they're a good installer.

 

 

[SteamyTea]

Only read your abstract of what you intend to do.

2 hours ago, Big Jimbo said:

I have sized this to give the chance to have three 10min showers at the same time, with the water being stored at 45c.

Does your incoming mains support this, there will be a drop in flow once all them bends in the pipes and the length of the pipe rums is taken into account.

2 hours ago, Big Jimbo said:

upstairs rads

 

2 hours ago, Big Jimbo said:

downstairs underfloor heating

Effectively two different types of heating systems.  Not a problem as suck, but needs a bit of careful thought re flow rates, flow temperatures emitter areas and the different heat distribution within a room i.e. where the radiators are located.

2 hours ago, Big Jimbo said:

a front sitting room, that i anticipate will be used mostly in the evening

As I am sure you have read from people that run their HPs efficiently, they are effectively 'on' all the time, so room usage is just a distraction.  Treat it as a room that is always at 21°C. (maybe a slight setback at night).

2 hours ago, Big Jimbo said:

Aprox 10 solar panels South facing, And 10 West facing

Fit as much as you can by all means, the marginal costs difference is minor, and maybe negative.

2 hours ago, Big Jimbo said:

don't have the budget for fitting any battery storage, but intend getting the various wires run while the house is being built

Don't think there will be need for additional wiring, but it does depend on if it is an AC or DC coupled system.  Initially get a suitable inverter for your capacity that is acceptable to your DNO i.e. how many amps you can connect per phase.

Worry about battery storage when you build the second house, the energy market will have changed (again) by then.

2 hours ago, Big Jimbo said:

have to fit an EV charger, although i dont have an electric car.

You have to fit one, so no point fretting about it.  If you put the cabling into conduit, you can fit another cable into it for battery storage (EV charge points are usually in a garage, where batteries may go in the future).

2 hours ago, Big Jimbo said:

150meters above Heathrow Airport

Bet that is (expletive deleted)ing noisy, fit quadruple glazing.

 

As an after thought, and replying to this

  

29 minutes ago, Mr Punter said:

So the first house you build is a spec development.  Buyers will not be very interested in the heating system, EPC score or airtightness, just location, what it looks like, number of bedrooms and price.

This is why some of us have to do the right thing, we cannot rely on others.  It also stops them having to know anything.

Edited 4 hours ago by SteamyTea

[Big Jimbo]

5 minutes ago, SteamyTea said:

 

Bet that is (expletive deleted)ing noisy, fit quadruple glazing

Fortunately a fair old distance away. However only a couple of hundred meters from One of the golfballs. Radar station about 50meters high. there are 3 or 4 around The outskirts of london. Used to track the planes into Heathrow. My weapons manufacturing son in law advises me that although not public knowledge, the stations are also used by the military. Apparently, that makes it on to the list of first of targets within the UK in the event of war. If that's the case i hope it's a nuke. I don't want to be hanging around. I'd rather be vapourised.

[SteamyTea]

2 minutes ago, Big Jimbo said:

couple of hundred meters from One of the golfballs

So bathed in warming microwaves.

2 minutes ago, Big Jimbo said:

Apparently, that makes it on to the list of first of targets within the UK in the event of war.

Non of us are far from a military base.

I used to live and work in High Wycombe, home of HG Air Command.

Now I am fairly close to RAF Portreath, and RNAS Culdrose.  Would have to cross a 'radiation' zone to get out.

 

[Oz07]

How much is your gas connection? Where i am the quote is normally in the hundreds not thousands. Like @Mr Punter I'd be wary of solar and heat pump on a spec build. Your house won't fetch any more money for having pv. They can always retrofit this themselves if the calcs work for them. Or do you need it for SAP pass?

Same story with the hear pump. You won't realise any more money for fitting one so just weigh up what is more expensive to install. Like @Mr Punter says you may in fact have some customers put off by an ASHP. It doesn't sound like they have a good rep round your way and the average punter is not going to be interested in visiting buildhub to find our how good they can be if they already have a negative perception of them. 

[Big Jimbo]

@Oz07 gas is already on site.

[JohnMo]

3 hours ago, Mr Punter said:

Do it for as little money as possible.

That's the trouble with this country - lowest standards possible. And a general public that are willing to accept that.

 

So a cheap 30kW combi that only modulates down to 10kW, thermostat in every room, boiler that lasts about 5 years because it cycles so often. That'll do 

[Adrian Walker]

You should aim to get a better air leakage of 3. 

[Big Jimbo]

47 minutes ago, Adrian Walker said:

You should aim to get a better air leakage of 3. 

At 1750square foot, it is a compact 4 bedroom, 3 bathroom house. Although i have designed for 5ach, i will aim to be better. However, i don't really have room for the ducting for MVHR, or the actual unit. That and the roof pitch is shallow at 28 degrees. It's also a cold loft space, and i have a height restriction.

[JohnMo]

1 minute ago, Big Jimbo said:

Although i have designed for 5ach, i will aim to be better. However, i don't really have room for the ducting for MVHR, or the actual unit

I would just a decent dMEV system.

[Mr Punter]

50 minutes ago, JohnMo said:

So a cheap 30kW combi that only modulates down to 10kW, thermostat in every room, boiler that lasts about 5 years because it cycles so often. That'll do 

 

No, system boiler and UVC.  Viessmann modulate down to 3.2kW and cost less than £900+VAT.  One stat and TRVs.

[Big Jimbo]

@Adrian Walker Also, i believe that at below 3 i would be required to fit MVHR. It is a shame but just really not got the space. I will have to have have 6 extractors for all the wet areas. I will have to have a look and consider what my options are on that front.

[Russell griffiths]

Why 3 bathrooms in a 4 bed that your selling

i would think the market would expect an en-suite to the main bed then a family bathroom on the first floor and cloakroom toilet downstairs. Saves  a big chunk of cash. 
what sort of houses are available locally and have you been to look at a few that will be in the price range you are aiming for. 

[Big Jimbo]

I have looked around locally, and spoken to two agents that i know well. Its felt that it is the best configuration for the local market. Nice master ensuite. double sink, double width shower. Bed 2 with small but functional en-suite. Beds 3 and 4 share a bathroom with separate bath and shower.