Insulation, ventilation, heating systems?

[misty1]

I am at roof level in a self build project. The block built house is a storey and a half and 3098 square feet.

Query 1 -I was going for a hrv system but i have an open fire so i have been told that it won't work with an open fire.
Query 2 - If hrv system doesn't work how do i ventilate the house. i am putting in triple glazed windows so trickle vents would defeat the purpose of triple glaze (said to me by window salesman). I am putting a 40mm board on the inside of the external wall which will be a six inch pumped cavity so do i put in wall vents if so do they have to be in every room or just kitchen and wet rooms. Any other suggestions..
Query 3 - i am thinking of putting in ufh upstairs and downstairs run off a air to water heat pump. Still unsure of this heating system, do not know much about it.. what pump would be sufficient for my size of house, is it severe on esb and would it need a back up heating system??? Any other suggestions..
Query 4 - Any suggestions on best way to insulate dormer bedrooms sun lounge roof..

Please advise, crucial decisions to be made by a rookie self builder..
Any advise would be greatly appreciated..

 

[Superman]

Query 1 -I was going for a hrv system but i have an open fire so i have been told that it won't work with an open fire.

Have you considered putting in a stove or a room sealed fire? They can work with HRV.
A HRV can work with an open fire - the issue is that you are pointlessly wasting money (say €5-6k) by sticking a large hole in your room (i.e. the chimney) while putting in HRV. So it is possible to do this.
An alternative compromise is to only have trickle vents in the room with the chimney (this will mess up your BER calculation - though it might not matter if you've room to spare in that).

Probably the best solution would be to go with [broken link removed]:
[broken link removed] - these guys do it (found them on google - I am not connected).

Query 2 - If hrv system doesn't work how do i ventilate the house. i am putting in triple glazed windows so trickle vents would defeat the purpose of triple glaze (said to me by window salesman). I am putting a 40mm board on the inside of the external wall which will be a six inch pumped cavity so do i put in wall vents if so do they have to be in every room or just kitchen and wet rooms. Any other suggestions..

Every habitable room.

Query 3 - i am thinking of putting in ufh upstairs and downstairs run off a air to water heat pump. Still unsure of this heating system, do not know much about it.. what pump would be sufficient for my size of house, is it severe on esb and would it need a back up heating system??? Any other suggestions..

On Air-Water heat pump - I don't like it. It works great at warming your house in summer (when the air is warm) and at cooling your house in winter (when the air is cold).
It is not so good if you want to warm your house in winter though... and the colder it gets, the worse it gets. It does exactly the opposite of what you'd want a heating system to do.
My advice: Put your money into insulation, go with a small oil boiler.

Query 4 - Any suggestions on best way to insulate dormer bedrooms sun lounge roof..

Insufficient information to comment.

General tip: Get a BER advisor (with construction experience - Architect, Technician, Engineer) to do a BER on your existing construction and advise where to go from from here.

 

[Sandals]

anyone i know with an openfire are sorry and are replacing them with stoves (included us) or fitting fireplaces that had a hatch you have to open when fire on/close when fire not on.

 

[buyingabroad]

Probably the best solution would be to go with [broken link removed]:
[broken link removed] - these guys do it (found them on google - I am not connected).

I'm currently installing this - retrofit diy job. Will let you know how I get on.

 

[Construct]

A HRV system will work in a house with an open fire but it's efficiency will be reduced. Will you light a fire often? If it is only a few occasions per year you might consider something to block the chimney. A fully working HRV system in a well insulated airtight house will leave you with lower heating bills and good indoor air quality 24/07. HRV systems are independent of the heating system in the house. They are air to air devices.

 

[threebedsemi]

What levels of airtightness are you aiming for misty1?
A Mechanical Ventilation Heat Recovery system will generally only be economical in a very airtight house (uncontrolled filtration at less than 5cu.m./[h.m] at 50 PA).

For a 'leakier' house a passive stack system may be a better option, though of course it dosent recover heat.

Another option you may consider is individual 'Heat Recovery Room Ventilators' which are in effect a MVHR for a single room. You would probably need three or four of them to adequately ventilate a house, and they can be a bit noisey.
You can source them via vent-axia, but as I haven't used them as yet myself I cannot vouch for them.

 

[Holly2010]

We have just installed a HRV system, the installer reckons any air loss is going against the system. Even an extractor in the kitchen should be sealed. We are puttin in a stove, but even those should have an external air supply fitted, in order that it doesnt take air from the room.

As for your query on insulation, we went with a timber frame kit and all insulation was supplied. The company advised us to install rigid foil insulation in any sloping ceilings, and we have insulated plaster board for around the dormer windows.

 

[RKQ]

I am at roof level in a self build project. The block built house is a storey and a half and 3098 square feet.

Please advise, crucial decisions to be made by a rookie self builder..
Any advise would be greatly appreciated..

I advise all my Clients of these options at pre-planning stage. I advise them to decide on these & similar issues before work begins on site. Waiting for Permission is an excellent time to investigate & resolve these issues.
Why haven't you sought advise from your Certifier / Designer and BER Assessor?

I'd agree with Superman on Query 1 & 2.

Query 3. Geothermal Heat pumps work, especially if the majority of heat is generated at night on cheap rate electricity. A back up is required for sub zero periods - a stove is fine.
Note - UK homes blocked up their chimneys as Gas heating became popular, this lend to a huge increase in Asthma cases - warm, moist, poorly ventilated homes were idea for the growth of dust mite population.
HRV would prevent this, as ventilation is critical. Salesmen may have opinions but your Designer / Certifier will understand the requirements of Building Control. Seek unbiased professional opinion.

UFH works up stairs with a concrete floor.

Query 4. Should be resolved by your Designer / Certifier. Seek advise from BER Assessor if necessary. There is not enough info here to comment.

 

[onq]

I am at roof level in a self build project. The block built house is a storey and a half and 3098 square feet.

Query 1 -I was going for a hrv system but i have an open fire so i have been told that it won't work with an open fire.

Its damned hard to recover heat when most of its going up the chimney.
You might consider one of the sealed fires.

Query 2 - If hrv system doesn't work how do i ventilate the house.

Open a window.

i am putting in triple glazed windows so trickle vents would defeat the purpose of triple glaze (said to me by window salesman). I am putting a 40mm board on the inside of the external wall which will be a six inch pumped cavity so do i put in wall vents if so do they have to be in every room or just kitchen and wet rooms. Any other suggestions.

Sounds like you haven't balanced up your insulation provision and have been listening to a very persuasive triple glazing salesman.
I have never been a fan fo pumped cavities, although a client used on in the last house I designed - the BER assessor claimed it achieved an A3 rating, so who am I to argue.

Query 3 - i am thinking of putting in ufh upstairs and downstairs run off a air to water heat pump. Still unsure of this heating system, do not know much about it.. what pump would be sufficient for my size of house, is it severe on esb and would it need a back up heating system??? Any other suggestions.

You need to get some expert advice on the specification of your house, not try to distill useful information on a wide range of services from sales pamphlets, the web, and product salesmen.
You need a good architect and a good M+E consultant, with either one or the other qualified as a BER assesor.
You need to consider the design of your house to take account of sun path, orientation, exposure and detail it to maximise incident sunlight and mniimise heat loss both through the fabric and through doors.

For example; don't go installing a cheap version of one of these wall-wide double folding window-door things for effect and then wondering why the threshold leaks or the house isn't well sealed.
Far better for you to design in a draught lobby with widely spaced doors for the most used doors front, rear and side access points than be spending a fortune on triple glazing, especially if you have kids.

Query 4 - Any suggestions on best way to insulate dormer bedrooms sun lounge roof..

Carefully.

Please advise, crucial decisions to be made by a rookie self builder..
Any advise would be greatly appreciated..

I advise you to employ building professionals on the biggest investment of your life to date and for your own sake, STOP LISTENING TO SALESMEN!

FWIW

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

 

[onq]

I advise all my Clients of these options at pre-planning stage. I advise them to decide on these & similar issues before work begins on site. Waiting for Permission is an excellent time to investigate & resolve these issues.
Why haven't you sought advise from your Certifier / Designer and BER Assessor?

I'd agree with Superman on Query 1 & 2.

Query 3. Geothermal Heat pumps work, especially if the majority of heat is generated at night on cheap rate electricity. A back up is required for sub zero periods - a stove is fine.
Note - UK homes blocked up their chimneys as Gas heating became popular, this lend to a huge increase in Asthma cases - warm, moist, poorly ventilated homes were idea for the growth of dust mite population.
HRV would prevent this, as ventilation is critical. Salesmen may have opinions but your Designer / Certifier will understand the requirements of Building Control. Seek unbiased professional opinion.

UFH works up stairs with a concrete floor.

Query 4. Should be resolved by your Designer / Certifier. Seek advise from BER Assessor if necessary. There is not enough info here to comment.

RKQ,

Geothermal heat pumps may work, but according to an M+E consultant I talked to a week ago, the shallow ones end up freezing the ground around the house, which can lead to problems in the winter, while the deep ones have an extended payback time.

I'd appreciate any competent life cycle costs on these systems including payback time at current and projected costs -vs- simply super-insulating the house envelope.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

 

[tomred]

Hi ONQ,

Just picking up on your comments above re the potential costs of Geothermal (or other such solutions) v super-insulation. I am researching this point at the moment as some of the feedback I am receiving is cautioning that solutions such as Geothermal can be very expensive to install and run and perhaps the money would be better spent on insulation / airtightness. Can I get your thoughts on what source heating solutions you would advocate where insulation / airtightness were to a very high standard. My proposed build is 3000 sq feet and I only have access to single phase electricity supply (this point needs to be confirmed but my research thus far tells me that single phase electricity does not work so well with Geothermal).

I am in planning phase and do have an architect but am doing my own independent research.

Thanks!!

 

[onq]

Good to see you doing your own research.

May I respectfully suggest you follow up RKQ - perhaps with a PM as he seems to have direct experience of them and hasn't reverted to me on this.

By all means revert here if you have no joy with him.

In the meantime here is an article from Construct Ireland which gives some information from Paul O'Donnell of Unipipe.

[broken link removed]

Here he is again commenting on Condensing Boilers

[broken link removed]

Obviously he's in the business of selling heat pumps but these links may help you find other information.

For the record I have no connection to Paul other than I know him socially.
I've seen him on other articles and I pass this on for what its worth.
I have not worked with Paul and so cannot comment in detail.

If you decide to take competent professional advice you could try; -
Colin Reid of Johnston Reid and Associates, Mechanical and Electrical Consulting Engineers.



Colin works all over the country and has never fluffed a question I asked - no small feat.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

 

[tomred]

Thanks for the information onq - much appreciated.

I will follow-up with RKQ separately.

I had already spoken with Colin Reid (following your advise on a separate thread- M&E consultant) and do plan to consult with him when I get my own head around the lingo!! On my initial telephone conversation he does come across as very straightforward so thanks for pointing me his way. He was not familiar with AAM so hopefully I converted him (if only to research where the recommendation came from!).

Thanks again
Tomred

 

[onq]

Well done for spreading the word about AAM, tomred.

I seldom recommend people but Colin is one guy I think very highly of.

Regards.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.