Heat Recovery System question

Shefwedfan

Hi, I have just completed a renovation on house. I didn't change the heating system just put in new radiators and better pipes etc. The current boiler is Grant boiler and I checked with Grant and no need to change.

I always had in back of heat about heat recovery but didn't have money in initial budget to install so now I am looking at it.

On the renovations I pumped the cavity, insulated slabs on walls and ceilings, put air tighness around the windows. Put in new floors with 100MM insulation under it etc.

I have no idea where to start on heat recovery, the house is 3,000sq ft and bungalow so plenty of attic space to install the system. I am just wondering is it any good? Should I look at other alternatives?

I checked with a few companies about heat pump but they said the cost to replace the radiators would be too much and just stick with oil.

KCross

What is your motivation for getting/wanting it? Do you have mould issues? Is the air stale at the moment and you open windows?

If you have an airtight house (which you allude to) then it makes sense to have it as you need fresh air in the house otherwise you will suffer mould issues.

Having HRV means you have clean fresh air 24/7 in the house and you have that without the huge heat losses you would suffer by opening windows.

Its not cheap though. You could install it yourself but you need specialist equipment to balance the system properly.

Shefwedfan

KCross wrote: »

What is your motivation for getting/wanting it? Do you have mould issues? Is the air stale at the moment and you open windows?

If you have an airtight house (which you allude to) then it makes sense to have it as you need fresh air in the house otherwise you will suffer mould issues.

Having HRV means you have clean fresh air 24/7 in the house and you have that without the huge heat losses you would suffer by opening windows.

Its not cheap though. You could install it yourself but you need specialist equipment to balance the system properly.

I don't have a large mould issue, maybe in bathrooms if I dont leave windows ajar all the time. The stale air is issue so most days we have to open majority of windows to freshen up the house. That is one of the main reasons.

Also correct me if wrong but the heat recovery will help reduce the heating bills? As I am recovering the lost heat? that would be another reason, it takes a fair bit of oil to heat house due to it been spread out.....

KCross

Shefwedfan wrote: »

Also correct me if wrong but the heat recovery will help reduce the heating bills? As I am recovering the lost heat? that would be another reason, it takes a fair bit of oil to heat house due to it been spread out.....

Correct, it will reduce heat loss hence reducing heating costs.

Personally, I love the system. The air is always fresh and we never open a window which helps to reduce the fly count as well!

Shefwedfan

KCross wrote: »

Correct, it will reduce heat loss hence reducing heating costs.

Personally, I love the system. The air is always fresh and we never open a window which helps to reduce the fly count as well!

That would be another major plus, I thought the fly season was over and now have another massive influx of them over the weekend.....

Do you mind me asking what system you got installed?

BryanF

Get an air-tightness test and report back

Shefwedfan

BryanF wrote: »

Get an air-tightness test and report back

Of course that would be part of the process.

I would be confident of house been in good condition. Even externally the original plaster was covered with monocouche plaster as well.....

All the interiors rooms are done with insulated slabs and then reskimmed fully.

KCross

Shefwedfan wrote: »

That would be another major plus, I thought the fly season was over and now have another massive influx of them over the weekend.....

Do you mind me asking what system you got installed?

Brink Renovent HR

On the installation side, try to locate the unit in an accessible location. You have to change/clean filters a few times a year and having to crawl into an attic for that will get old quickly!


I also added wireless boost buttons so if there is a lot of steam (kitchen, showers or other unwanted smells etc) you can press a button on the wall and it boosts the unit up to max speed to quickly replace the air and automatically returns to normal speed in 15mins. Its less efficient when boosted but its irrelevant when its just 15mins.

rolion

Hi,

Highly recommended !
I did a DIY purchase / install some time ago,read more H E R E .
Couldnt live without !
Have fun ...

SemperFidelis

I did a DIY retrofit of MVHR a year ago to a 1970s house. I wouldn't be without it now. The house suffered from mould and was always stuffy. It always feels fresh now and mould is no longer an issue. The house is far from airtight but whenever I do any work on a room I'll try to closeup any air leaks as much as I can. It took a couple of days to install but wasn't too difficult. Balancing the system takes a while.

Example of temperatures;

Air into unit 13.8
Air out of unit 16.1
Air into house 19.4
Air out from house 19.3

During winter I got these;

Air into unit 0.6
Air out of unit 7.5
Air into house 15.6
Air out from house 18.3

Shefwedfan

Seems everyone is doing a DIY installation, any reason why?

I would expect a company to come in and install

rolion

Shefwedfan wrote: »

Seems everyone is doing a DIY installation, any reason why?

I guess there are two tyes of man: one that presses the button and stops there and other type,that presses the button and "pray" it will work.

Personal,i love the fun,the xperience,the challenges,the wife screaming "finish tomorrow or take it out",the all the diy work that you said to yourself it will be like that for a day or even after one year,same location and situation (temporarily is the new permanent) and not lastly and most of the time, the dooh moment when i am saying to myself "i will do it better next time" !
Cost,i guess comes somewhere too...

Shefwedfan wrote: »

I would expect a company to come in and install

Yes,there are compnaies that specialises in this area.
I can PM you my lads,based in Dungarvan that assist me with parts and "know-how" .

Either type of man you are,i wish you good luck...

Shefwedfan

rolion wrote: »

I guess there are two tyes of man: one that presses the button and stops there and other type,that presses the button and "pray" it will work.

Personal,i love the fun,the xperience,the challenges,the wife screaming "finish tomorrow or take it out",the all the diy work that you said to yourself it will be like that for a day or even after one year,same location and situation (temporarily is the new permanent) and not lastly and most of the time, the dooh moment when i am saying to myself "i will do it better next time" !
Cost,i guess comes somewhere too...



Yes,there are compnaies that specialises in this area.
I can PM you my lads,based in Dungarvan that assist me with parts and "know-how" .

Either type of man you are,i wish you good luck...

Majority of work I do myself to be honest, the only bits I don't touch is electrical and plumbing. Electrical because I would probably kill myself or someone else and plumbing because I will flood the place :P small jobs of course I will do but anything big and I use "the guy"

I would expect this to be a big job, I guess I need to run ducting to every room? So I would need to run to 14 rooms without counting 2 halls. I think it might be a step too far for me to be honest.

Could you send on details please

The other question, I have a large sun room(4m x 6m) which has the usual problem(too warm or too cold). Would the Heat recovery potentially help with this room?

My current plan is whip off roof and replace with light weight roof to try control the heat....

Dardania

The simpler solution for retrofit could be DCV. Obviously not as good as HRV, but may be more practical.

rolion

Shefwedfan wrote: »

Majority of work I do myself to be honest, the only bits I don't touch is electrical and plumbing. Electrical because I would probably kill myself or someone else and plumbing because I will flood the place :P small jobs of course I will do but anything big and I use "the guy"


I would expect this to be a big job, I guess I need to run ducting to every room? So I would need to run to 14 rooms without counting 2 halls. I think it might be a step too far for me to be honest.
Could you send on details please


The other question, I have a large sun room(4m x 6m) which has the usual problem(too warm or too cold). Would the Heat recovery potentially help with this room?

My current plan is whip off roof and replace with light weight roof to try control the heat....

I find your level of approach very wise and very enjoyable,same for me,as long as "we" know what "we're" doing and knowing the limits / boundaries !

If you look at my DIY thread,you will see is not a big diy job..BUT..always a but,you will need skills of a plasterer,painter and be light and flexible for how many holes,corners and joists you will need to meet !
Is easy on the rooms below attic and gets harder with the rooms on the groundfloor.

Re sunroom,you can use it to extract the heat / hot air and warm up other rooms day time / early evennig but not sure how and if you can fit the an inflow and an outflow in same room AND opposite directions to cool it down with MHRV.Ask for advice ...

listermint

SemperFidelis wrote: »

I did a DIY retrofit of MVHR a year ago to a 1970s house. I wouldn't be without it now. The house suffered from mould and was always stuffy. It always feels fresh now and mould is no longer an issue. The house is far from airtight but whenever I do any work on a room I'll try to closeup any air leaks as much as I can. It took a couple of days to install but wasn't too difficult. Balancing the system takes a while.

Example of temperatures;

Air into unit 13.8
Air out of unit 16.1
Air into house 19.4
Air out from house 19.3

During winter I got these;

Air into unit 0.6
Air out of unit 7.5
Air into house 15.6
Air out from house 18.3

Have a rough estimate of your costs.

Always something I was Interested in, currently refurbishing a 1970s bungalow. Going through wall pumps and external insulation, boxed the windows out and draft sealed. It's currently heated by oil but I don't like the idea long term.

Good quality air has always appealed to me.

Shefwedfan

rolion wrote: »

I find your level of approach very wise and very enjoyable,same for me,as long as "we" know what "we're" doing and knowing the limits / boundaries !

If you look at my DIY thread,you will see is not a big diy job..BUT..always a but,you will need skills of a plasterer,painter and be light and flexible for how many holes,corners and joists you will need to meet !
Is easy on the rooms below attic and gets harder with the rooms on the groundfloor.

Re sunroom,you can use it to extract the heat / hot air and warm up other rooms day time / early evennig but not sure how and if you can fit the an inflow and an outflow in same room AND opposite directions to cool it down with MHRV.Ask for advice ...

I know my limits, I have pushed them before to reasonable success but I feel this might be step too far

Access to room is not an issue as bungalow. I attached the image of house.

It is very spread out and I would guess I need a lot of ducting going around the attic.

The attic has plenty of space to walk around etc.....

Dardania

Shefwedfan wrote: »

rolion wrote: »

I find your level of approach very wise and very enjoyable,same for me,as long as "we" know what "we're" doing and knowing the limits / boundaries !

If you look at my DIY thread,you will see is not a big diy job..BUT..always a but,you will need skills of a plasterer,painter and be light and flexible for how many holes,corners and joists you will need to meet !
Is easy on the rooms below attic and gets harder with the rooms on the groundfloor.

Re sunroom,you can use it to extract the heat / hot air and warm up other rooms day time / early evennig but not sure how and if you can fit the an inflow and an outflow in same room AND opposite directions to cool it down with MHRV.Ask for advice ...

I know my limits, I have pushed them before to reasonable success but I feel this might be step too far

Access to room is not an issue as bungalow. I attached the image of house.

It is very spread out and I would guess I need a lot of ducting going around the attic.

The attic has plenty of space to walk around etc.....

Indeed a lot of ducting, and due to the length of runs ther,e you'd need to be spot on with balancing airflow etc.

SemperFidelis

rough breakdown as requested;

MVHR unit - €1400
27m of 150mm Spiral Steel Ducting - €100 (I got too much of this)
bends for above - €100 (use 2 x 45 bends instead of 1 90 for better air flow)
50m semi rigid duct - €150
Duct Insulation roll - €100
9x Plenum boxes - €200
2 x Distribution boxes - €100
ceiling valves - €60
external grilles - €40
Duct sealant 5 tubes - €30
Flexible ducting - €20 (to connect unit to steel duct)
core bit - €50

So you could get the bits and pieces for about 2500 for a house under 150m3, you'd need a bigger MVHR unit for a bogger house. the next unit up was about €250 more.

I'm still using oil to heat, but all the hole in the wall vents are now filled in and many drafts eliminated. Its still not perfect but the air quality is infinitely better.

listermint

SemperFidelis wrote: »

rough breakdown as requested;

MVHR unit - €1400
27m of 150mm Spiral Steel Ducting - €100 (I got too much of this)
bends for above - €100 (use 2 x 45 bends instead of 1 90 for better air flow)
50m semi rigid duct - €150
Duct Insulation roll - €100
9x Plenum boxes - €200
2 x Distribution boxes - €100
ceiling valves - €60
external grilles - €40
Duct sealant 5 tubes - €30
Flexible ducting - €20 (to connect unit to steel duct)
core bit - €50

So you could get the bits and pieces for about 2500 for a house under 150m3, you'd need a bigger MVHR unit for a bogger house. the next unit up was about €250 more.

I'm still using oil to heat, but all the hole in the wall vents are now filled in and many drafts eliminated. Its still not perfect but the air quality is infinitely better.

Cheers. Sounds far more reasonable than I had thought. Well up or. Installing this presently going througu rsj installations and knocking walls running ducts and cutting Plaster is a piece of..


Did you source everything in Ireland?

rolion

Hi,

My HRV reading in the morning.
My little secret is that i ran a short intake pipe from the so called utility / hot press room (where my hot water cyinder is located) straight in to the intake manifold of the HRV.
That assures a constant hot air from that closed warm room in to the path of the heat exchange.
Dont need to extract the air from there but is very warm(i could say depsite the good cylinder and pipes insulation) that is the warmer room in the house!

crf450

KCross wrote: »

What is your motivation for getting/wanting it? Do you have mould issues? Is the air stale at the moment and you open windows?

If you have an airtight house (which you allude to) then it makes sense to have it as you need fresh air in the house otherwise you will suffer mould issues.

Having HRV means you have clean fresh air 24/7 in the house and you have that without the huge heat losses you would suffer by opening windows.

Its not cheap though. You could install it yourself but you need specialist equipment to balance the system properly.

KCross wrote: »

What is your motivation for getting/wanting it? Do you have mould issues? Is the air stale at the moment and you open windows?

If you have an airtight house (which you allude to) then it makes sense to have it as you need fresh air in the house otherwise you will suffer mould issues.

Having HRV means you have clean fresh air 24/7 in the house and you have that without the huge heat losses you would suffer by opening windows.

Its not cheap though. You could install it yourself but you need specialist equipment to balance the system properly.

Is main reason for this system if you suffer from mould in a house ? or could you install in new build as heating system instead undefloor heating or rads ??

KCross

crf450 wrote: »

Is main reason for this system if you suffer from mould in a house ? or could you install in new build as heating system instead undefloor heating or rads ??

Its not a heating system. Its a ventilation system.

If you have an airtight house you need a way to get fresh air in without loosing masses of hard earned heating.

crf450

KCross wrote: »

crf450 wrote: »

Is main reason for this system if you suffer from mould in a house ? or could you install in new build as heating system instead undefloor heating or rads ??

Its not a heating system. Its a ventilation system.

If you have an airtight house you need a way to get fresh air in without loosing masses of hard earned heating.

Ah very good, I thought It was way of heating a house my bad thanks for clearing up .

rolion

crf450 wrote: »

Ah very good, I thought It was way of heating a house my bad thanks for clearing up .

Your thinking is not bad...as a secondary effect on the fresh air / warm air works ... i could say that the temperatures are constant and even across all the home'rooms and corners ! Thats due to the air flowing from the ceilling vents, air lifted by the radiators and the "push and pull" by the vents instlled across the house.

Shefwedfan

Ok, I havent done much on this yet. just considering how to approach.

What I was thinking, which is probably madness, at the moment in attic there is between 100-400mm of fibre glass insulation. I bloody hate the stuff. What I was thinking of doing was pulling it all out and then spray foam between the joists. This would help with air tighness and also mean I can floor out sections of attic to use for storage space.

I know normally you spray foam between rafters so is it possible to spray between the joists? is this a mad approach?

rolion

@shefwedfan
I will say your priority is to get your home (walls,ceillings,concret,timber,plaster board) as healthy as possible !
With a well insulated house,issues will arrive and it may be too late to correct as you overlooked at it or you are way over the budget (both happened and experienced on my own pocket)

Have fun..

Shefwedfan

rolion wrote: »

@shefwedfan
I will say your priority is to get your home (walls,ceillings,concret,timber,plaster board) as healthy as possible !
With a well insulated house,issues will arrive and it may be too late to correct as you overlooked at it or you are way over the budget (both happened and experienced on my own pocket)

Have fun..

I have new floors with 100mm insulation under them, new walls with 60mm insulated slabs, on majority of ceiling I also put insulated slab onto them of 60mm. Pumped the cavity as well..... On the windows I put on air tightness tape before I re-skimmed not too shabby

The bit I haven't touched is the attic insulation. Mainly because the house must have had a rat issue before and loads of rat poo on the insulation. Some sections have 400mm and some section as little as 100mm

I am just wondering what would be the best insulation to install into the attic, once i have that done the heat recovery would come next

One job at a time

Dardania

Shefwedfan wrote: »

rolion wrote: »

@shefwedfan
I will say your priority is to get your home (walls,ceillings,concret,timber,plaster board) as healthy as possible !
With a well insulated house,issues will arrive and it may be too late to correct as you overlooked at it or you are way over the budget (both happened and experienced on my own pocket)

Have fun..

I have new floors with 100mm insulation under them, new walls with 60mm insulated slabs, on majority of ceiling I also put insulated slab onto them of 60mm. Pumped the cavity as well..... On the windows I put on air tightness tape before I re-skimmed not too shabby

The bit I haven't touched is the attic insulation. Mainly because the house must have had a rat issue before and loads of rat poo on the insulation. Some sections have 400mm and some section as little as 100mm

I am just wondering what would be the best insulation to install into the attic, once i have that done the heat recovery would come next

One job at a time

perhaps the other way round - that way you can insulate the finished ductwork opes etc. nicely (rather than breaking through fresh work...)

SeanHarty

crf450 wrote: »

Is main reason for this system if you suffer from mould in a house ? or could you install in new build as heating system instead undefloor heating or rads ??

A MVHR system cant be used as a stand alone heating system but it will indeed reduce the heat losses across the house resulting in a smaller boiler/heat pump, also smaller radiators if that's how your delivering the heat.