Heat recovery on a Small House

CPTM

Hi all - I'm trying to find a unit that would suit a small cottage. It's only 40m^2 with 4 rooms and all the units I've seen so far seem to be designed for larger houses (100m -600m).

Can anyone help or point me in the right direction? One quote was €4,000, I'm wondering if there's a smaller unit that might lower the cost.

MicktheMan

Have you considered an alternative type of system such as DCV? Given the size of the cottage, have you worked out the cost of the expected ventilation heat loss without heat recovery?

CPTM

Hi MickTheMan, thanks for getting back to me. This was suggested but I'm looking for something that directly pumps new air in to or out from (in case of the bathroom) the rooms. There are no vents currently which means I need to keep my window open over night or my room gets stuffy. Similarly for safety in the kitchen where I have a gas fire, boiler and cooker I need to keep the windows open to ensure ventilation.

It would just be nice if I could get fresh air into the rooms without losing too much heat.

Dudda

You can get small heat recovery units that are designed for apartments. For example the Zehnder Comfoair 160 will suit flats and appartments up to 100sqm. Picked Zehnder as an example as it's the brand I'm looking at but all companies do smaller units. http://www.zehnder.co.uk/products-and-systems/comfortable-indoor-ventilation/zehnder-comfoair-160
It's also good to have a heat recovery on the slightly larger size as you can run it at a lower speed which is cheaper and quieter and can be boosted while having a shower or cooking to remove steam and odors.

CPTM

Small update folks. A unit was delivered but the size is way bigger than what was posted on the website. It doesn't fit in the attic! So it will need to be returned and it's back to the drawing board for me.

Due to lack of space amd small size of the house, I'm now looking at dcv, or anything that can replace the air in the house. My problem is that there are zero vents in the house and I'd rather keep it that way. The dcv units I can see seem to blow air into the house but don't seem to extract it any where. So I'm not sure where the displaced air goes in an airtight house. Does anyone know of a unit in Ireland that brings fresh air into the house on a controlled basis and extracts air out, say from the bathroom/kitchen?

The house is 40m squared, at this stage I might just open a window but I'm really keen on getting some form of air replacement system in.

BryanF

Dcv extracts to centralised extract fan from wc's, kitchen, drying room etc
Dcv intakes (wall vents with rh sensors controlling grills that close) will be in bedrooms and living spaces etc.

Gas boiler /stoves may need separate vents.

CPTM

Thanks BryanF, so there's no way of doing the same without vents being installed? If only there was a small machine that could extract air from one side of the house and pump air into the other whenever the air quality dropped.

If anyone has any recommendations it would be great to know. Vents are difficult to install in the house I'm living in, because the walls are 3/4 foot deep.

BryanF

Intake: window vents might suit
Extract: could be through the roof

CPTM

BryanF wrote:

Intake: window vents might suit Extract: could be through the roof

Thanks, another idea I have is having an input ventilation system and a vent inserted into a fireplace that's been plastered over in the sitting room. So fresh air blowing into the bedrooms and sitting room, and let the displaced air go up the chimney in the sitting room which is pretty central. Just missing a solution for the bathroom, but maybe a standard extraction fan would do the job there like what's in the kitchen.

BryanF

Best of luck with your project

Start here http://www.housing.gov.ie/housing/building-standards/tgd-part-d-materials-and-workmanship/technical-guidance-documents

Read documents B,F,J & L and report back

Calahonda52

OP: just reading some of the posts here you are beginning to stray off the reservation a bit as to what you are considering here.

While the capital cost of any mechanical ventilation system will be disproportionate because of the size of the house, if you are set in your ways in your aversion to wall vents, then look at smaller MHVR units: they are around
for example look here
http://www.envirovent.com/home-ventilation/products/heat-recovery-systems/

I would also think that you need to price up fitted dcv with fitted MHVR, i suspect there won't be much difference as the holes in the wall could set you back €150 or so a pop minimum.

The final point is that IAQ is much more important than other elements of a refurb and I am concerned that with the clear lack of expertise available to you and perhaps an aversion to seeking, and paying for, proper professional advice, the end result with be at best sub-optimal and at worst in breach of regs and perhaps potentially injurious to the occupants.

IAQ is indoor air quality
Keep well and good luck.

rolion

CPTM wrote: »

Small update folks. A unit was delivered but the size is way bigger than what was posted on the website. It doesn't fit in the attic! So it will need to be returned and it's back to the drawing board for me.

Due to lack of space amd small size of the house, I'm now looking at dcv, or anything that can replace the air in the house. My problem is that there are zero vents in the house and I'd rather keep it that way. The dcv units I can see seem to blow air into the house but don't seem to extract it any where. So I'm not sure where the displaced air goes in an airtight house. Does anyone know of a unit in Ireland that brings fresh air into the house on a controlled basis and extracts air out, say from the bathroom/kitchen?

The house is 40m squared, at this stage I might just open a window but I'm really keen on getting some form of air replacement system in.

Not sure if that helps you but i had to cut AND adjust a lots of things in my home and in the attic to accomodate the new hrv unit.
It works perfectly now but i can tell you it was so much fun cutting,drilling and doing the plaster and painting work.

A friendly advise is to go with a standard unit and see if you can adjust the house. A 300mc unit running at the half of paramaters will prolonge the life time and keep you under cash control. Some suppliers have wall mounted or vertical / horizontal unit !

Is not same scenario like delivering and installing a TV unit !

CPTM

Thanks for the additional info everyone, really helpful especially the links. It's not really an aversion to wall vents, it's more that they are pretty much impossible due to a combination of wall thickness, neighbours not wanting me messing with the wall that faces them, and all of that under a flat roof. Currently there are flat roof skylights with side vents built in which are fine but I can't seem to replace them with ones which are equally good (and dear God do they need replaced!).. I'm not worried about the mess, this is all part of a renovation project here spending 10-15k getting the house done once and for all. So the place is a mess right now regardless of this!

Sorry if I'm straying from the one approach, I am staying with the same primary target - fresh air in my room without a wall vent if possible. I think the latest set of links have given me more options - thanks for that.