Single room MVHR

[Tony359]

Hello all,

 

I would like to install an MVHR in my 25sqm garage which is my DIY room. I've insulated it (it was a big DIY project!) and in Winter time when I try to keep all cold air away, the air can get stale. Also, I am doing soldering for electronics and the fumes can build up over time.

 

Ideally I don't want to invest a huge amount of money on a machine as it's for the garage. I don't want one of those machines which you install at the wall as I understand they can only move air in one direction, hence the fan will periodically reverse direction. I don't think they can be as effective. 

 

I found this online but I'm concerned it might be a gimmick. https://www.ebay.co.uk/itm/115483101460

 

Any opinions on that? The unit would be installed above the ceiling. If anybody has any products to suggest, please by all mean do let me know!

 

Thank you!

[Adsibob]

Welcome Antonio. I would stay clear of unknown eBay retailers, and instead go with a company such as Bpc or CVC who can give you a free design service.

 

 Something like one of the cheaper units from here might work well:

 

https://www.bpcventilation.com/heat-recovery/heat-recovery-units/vent-axia-unit

 

How high is your ceiling, or how do you feel about boxing in some ducts on two sides of the room? I ask because given you plan on creating fumes, I would be tempted in having three fresh air supplies scattered around on one side of the room, and at least two extracts on the other side. This will require a ceiling void or some boxing in to conceal the ducting. Having said that, you can get low profile rectangular ducting that only needs about 7cm of height.

Edited November 1, 2023 by Adsibob

[Hastings]

Not a gimmick I think although the efficiency of 75% seems low - might be because of the small size compared to normal ones that are for a whole house.

 

BPCVentilation are popular with self-installers on this forum and offer single room units £300 and upwards. They would advise better than I can.

[JohnMo]

HiI would just do dMEV fan set on the lowest rate.

 

Here is what I would recommend, have done a comparison of running cost and heating savings below.

 

https://www.ebay.co.uk/itm/110918389829?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338749401&toolid=20006&customid=GB_11700_110918389829.141234980085~1871630609920-g_CjwKCAjwkY2qBhBDEiwAoQXK5d0Y4QsG2U9JPC4jZvEMGuxN-nZ8u5PCl84Yx8sUrwsA3kzKB7p8xhoCLtUQAvD_BwE

 

Advantages of dMEV

Silent in operation, no filters to change, one hole in the wall, will manage humidity boost out the box. Next to no power input.

 

Doing MVHR will cost way more install and run,  require loads more labour to install, require frequent filter changes as the flux, will mess with the extract filter.

 

If you are pretty well insulated your typical (14 deg delta between inside and outside) would require 500W with dMEV, and if MVHR is 70% efficient about 400W per hour heat input. (Used a heat loss calculations I had already as indicative)

 

180 heating days for 8 hours a day about £30-40 a year difference in heating cost.

 

But add in running costs, MVHR is 40W 24/7 so that is £94 per year, and additional filter changes - running at a low speed would possibly half that to say £40 per year. The dMEV would be running 24/7 all year also, but only requires between 0.5 and 1W at it's lowest set speed. So costs £2.30. Costs are based on 27p kWh.

 

So difference in heating saving is taken up in running costs, plus it costs way more to install MVHR (equipment and labour). I went through the same dilemma earlier in the year, and want Greenwood dMEV. No regrets

[Tony359]

Thanks for all the replies.

 

@JohnMo

Well "pretty well insulated" is a big statement. I still have (insulated) shutters which can let in cold air as they're still shutters after all. The walls have 25mm insulation (plus drywall and a gap) and ceiling is 100mm. Floor is only a 6mm sheet plus rubber tiles. What I want to say is that it's "insulated" to a point where it's comfortable to work with the heating on but when it's cold outside my heat pump works at minimum all the time. I have installed some thick curtains over the shutters to keep the heat in but as I said I'd like some fresh air coming in. Installing extractors means even more cold air would be drawn in which is going to translate to more energy required to heat the space. I am a DIY'er, I have no problems installing the MVHR by myself. It doesn't have to run all the time, mostly when I am using the space. 

 

Thanks for recommending BPCVentilation, I'll take a look!

 

@Adsibob

I have space above the ceiling, I can run all the ducts I want there

Soldering fumes is not a lot, but over many hours it can build up. This is nothing like welding fumes or cigarette smoke etc. I was thinking of just a single inlet and a single outlet to be honest.  Ceiling height is 240cm.

 

I did stumble into the Vent-Axia - it's still £380 which is £130 more expensive than the one from Ebay. With pipes and fittings (I'll do the install) it's way over £400. Obviously the old say "you get what you pay for" is very well in front of me

 

Thank you!

[Tony359]

I've taken a look at the options, the Vent-Axia seems to be the only budget option available. I've seen a picture of the inside and it looks very basic. The one I found on Ebay (which comes from a place called "the Ventilation Magastore, they do have a website) really looks like a Chinese thing with axial fans of unknown brand

 

There is a nice Blauberg available on Ebay which internally looks vastly superior to the VentAxia (also a bit more efficient but still below 80%) - it's also more expensive but I guess it could be ok. However even though Brand New I cannot think of buying a unit from Ebay when the manufacturer won't probably honour the warranty.  https://www.bpcventilation.com/media/catalog/product/b/l/blauberg_ultra_d105-a_data_sheet.pdf  (the datasheet is on the BPC website but they don't sell it).

 

Can someone help me understanding the below, from Blauberg datasheet?

 

The KOMFORT Ultra D 105-A unit is equipped with a plate cross-flow polystyrene heat exchanger for heat recovery. The unit condensate is collected and drained to the drain pan under the heat exchanger.

The KOMFORT Ultra D 105 unit is equipped with an enthalpy plate cross-flow heat exchanger for energy (heat and humidity) recovery. Due to humidity recovery condensate is not generated in the enthalpy heat exchanger.

 

I don't see any other options. Anything else is much more expensive and for multi-room service. Unless someone can point me to a different direction!

Edited November 2, 2023 by Tony359

[Adsibob]

I think you should call the various suppliers:

BPC

CVC Systems

ventilation land 

 

and ask them to recommend and supply a basic machine.

 

 Being a garage, you probably don’t care too much about how noisy it is, and just something that is durable and problem free. For just a one room garage, I don’t think the difference between 80% efficiency and 90% efficiency will make any noticeable difference to your heating bills. I guess it depends how you are heating it and what the heat loss is, but unless it’s really bad, a 10% differential shouldn’t make much difference.