heating for a new house?

water-man

Hello,

Looking for some advice regarding heating system for a new build, 200m^2. I will be insulating and making it as air tight as I can.
My thoughts around the heating system are:
• Stove with external air supply and gravity feed back boiler for DHW only.
• UFH in all rooms powered by a heat pump
• MHRV to all rooms, except sunroom
• 1000L hot water tank
• Thermostats in nearly all rooms to individually control UFH
Is this a realistic approach? I have some concerns if people could give their opinion I’m interested to hear all thoughts.
My concerns:
1. How to provide DHW on days I have no fire on? Will I need an electric element to boost the HP
2. Would you place an extraction vent near the stove to circulate the hot air to other rooms using the MHRV? Is this practical or a waste?
3. Are HP classed as renewable? They require electricity for the grid to run so what I will save in oil I’ll be paying for in electricity, oil price increase = electricity price increase.
4. Are the maintance cost of HP and MHRVs high (regular service, filters etc)
5. Is solar thermal an option for consistent UFH?
6. MHRV, what are the running cost like?
7. IS MHRV really practical with children running in and out of the house?
8. HP should I consider air to water or ground source? What are pros and cons of each?
9. Am I missing anything in my system?
10. What would be a rough price to install a system like this?
All feedback is wanted.

Thanks,
WM

fclauson

water-man wrote: »

Hello,

Looking for some advice regarding heating system for a new build, 200m^2. I will be insulating and making it as air tight as I can.
My thoughts around the heating system are:
• Stove with external air supply and gravity feed back boiler for DHW only.
• UFH in all rooms powered by a heat pump
• MHRV to all rooms, except sunroom
• 1000L hot water tank
• Thermostats in nearly all rooms to individually control UFH
Is this a realistic approach?

in a well insulated house you will keep the whole house at 20 degrees so thermostats are not needed

I have some concerns if people could give their opinion I’m interested to hear all thoughts.
My concerns:
1. How to provide DHW on days I have no fire on? Will I need an electric element to boost the HP

most HPs have a h/w facility which is more efficient than using an immersion

2. Would you place an extraction vent near the stove to circulate the hot air to other rooms using the MHRV? Is this practical or a waste?

air flows are so slow that it will have little effect

3. Are HP classed as renewable? They require electricity for the grid to run so what I will save in oil I’ll be paying for in electricity, oil price increase = electricity price increase.

they are renewables - but get a BER done to check

4. Are the maintance cost of HP and MHRVs high (regular service, filters etc)

filters - yes about €50 per set - needed twice a year
HPs - very little

5. Is solar thermal an option for consistent UFH?

do you pricing - in a new build solar thermal is not cost effective

6. MHRV, what are the running cost like?

do the maths - all units come with Watts per hour

7. IS MHRV really practical with children running in and out of the house?

yes - children only run in and out when they are then - you still need to ventilate over night and when you are away

8. HP should I consider air to water or ground source? What are pros and cons of each?

9. Am I missing anything in my system?
10. What would be a rough price to install a system like this?

get quotes and compare

All feedback is wanted.

Thanks,
WM

water-man

Hi fclauson,

Thank you for the response. I have no family or friends in construction or any who have gone down a self build route.

Could I ask if you would you know of any companies (MHRV & HP) that you could send me links/numbers to. PM me if not allowed to name companies.

The thermostat point is interesting. I had assumed rooms facing south would potentially need less heating thus the need for room stats. Something for me to think about.

If anyone has any light reading on this subject I'd be interested in getting my hands on it.

WM

zrejvpx

Our GSHP supplier recommended against having stats in each room. You could adjust the flows from the manifold so that some (e.g. north facing rooms) get more of a flow (and therefore more heat) than the area where the controller measures the temperature (but I haven't bothered)

muffler

I've moved a couple of posts to here as someone was looking for recommendations for suppliers which was not contributing to this thread as such.

muffler

The next person that attempts to hijack this thread by looking for recommendations instead of engaging in discussion will be banned from the forum

john_cappa

@fclausan: Just to clarify what you are saying, do you mean that if the house is well insulated/airtight then the MVHR will keep the temp constant overall so individual controlls are not required?

@OP why no MVHR in the sunroom?

fclauson

john_cappa wrote: »

@fclausan: Just to clarify what you are saying, do you mean that if the house is well insulated/airtight then the MVHR will keep the temp constant overall so individual controlls are not required?

@OP why no MVHR in the sunroom?

No - the UFH is at the same temp throughout the house - this keeps the constant temp - the MVRH provides the ventilation

please do not be fooled into thinking that your MVHR will move enough heat around the house to keep it warm - I do not believe this works practically

john_cappa

fclauson wrote: »

No - the UFH is at the same temp throughout the house - this keeps the constant temp - the MVRH provides the ventilation

please do not be fooled into thinking that your MVHR will move enough heat around the house to keep it warm - I do not believe this works practically

Perfect.

fclauson

also - the HP is always on - day and night - I let it work out when to top up the heat (based on return temps from the floor)

I have tweeked this slightly as I have PV and cheap overnight electricity so I

turn it off from 6am to 10am(with the hope PV will be on by then)
off at 5pm and back on at 11pm when overnight rate kicks on again

water-man

john_cappa wrote: »

@OP why no MVHR in the sunroom?

No HRV in sun room as down stairs living area will be all open plan and as sun room is part of this I see no need to run ducting to this room as it would involve the longest run.

Other thoughts since my inital post:

Will not have room stats

Will not have a stove with back boiler for water. I've begun thinking about a stove which heats air instead of water and blows this heat to rooms

Am thinking about an immersion plumbed into the Hot water tank only to be used incase the HP was to breakdown some day

Regards,
Water-man

fclauson

water-man wrote: »

• Will not have a stove with back boiler for water. I've begun thinking about a stove which heats air instead of water and blows this heat to rooms

you won't need it - with UFH it will keep the whole house at one temp

• Am thinking about an immersion plumbed into the Hot water tank only to be used incase the HP was to breakdown some day

HP systems come with immersions built in - mine has been on 1hr since October last year !!!!

water-man

fclauson wrote: »

you won't need it - with UFH it will keep the whole house at one temp

HP systems come with immersions built in - mine has been on 1hr since October last year !!!!

Does your Hot water come directly from the tank or is there another heat exchanger type (i.e hot water in tank heats the "cold" water going passed and thus becomes "hot" water) going on?

Or does your heat pump heat the tank to 60C as I had read that most go to 50C only and need the immersion to heat water to 60 to kill potential diease?

Regarding not needing the stove, i think a living room wouldn't feel/look right with out one - guess thats a personal thing.

WM

fclauson

water-man wrote: »

...

Regarding not needing the stove, i think a living room wouldn't feel/look right with out one - guess thats a personal thing.

WM

Certainly true - cannot sit around UFH drinking a wee dram