[James T aka Mr. James T]

just doing my new build at the moment i understand the idea of MHRV but am sick of cowboy salesmen telling me its all that. From all the posts on it with people pm-ing each other company names I know I am not the only one.
My build is block build I intend getting it as Airtight as possible but what about the Demand Controlled Vents.
It is half the price, no maintenance and no cowboy salesmen as far as i can see.
Anyone else any experience similar

[James T aka Mr. James T]

just the fact anyone i have asked that have it say they dont know if it is a good job or not.
i have not met anyone with it in 10 yrs or more.
i have big questions regarding maintenance after 10 or more years
i do understand the workings of it and i do not intend leaing gaping holes in my walls just controlled holes

[BryanF]

Originally Posted by James T aka Mr. James T

just the fact anyone i have asked that have it say they dont know if it is a good job or not.
i have not met anyone with it in 10 yrs or more.
i have big questions regarding maintenance after 10 or more years
i do understand the workings of it and i do not intend leaing gaping holes in my walls just controlled holes

I have spec'd DcMEV on retrofits but on new builds where you have the opportunity to plan layouts, high insulation and air-tightness levels recovering the heat makes sense. Perhaps you need to pick the top three international manufacturers and liaise with their technical departments and avoid the sales reps..

[sydthebeat]

Originally Posted by James T aka Mr. James T

just doing my new build at the moment i understand the idea of MHRV but am sick of cowboy salesmen telling me its all that. From all the posts on it with people pm-ing each other company names I know I am not the only one.
My build is block build I intend getting it as Airtight as possible but what about the Demand Controlled Vents.
It is half the price, no maintenance and no cowboy salesmen as far as i can see.
Anyone else any experience similar

demand control is much better from a heat loss point of view than 'hole in the wall;..but obviously doesnt have heat recovery.

it sounds like youve made your mind up on the matter so im not about o start trying to convert you... but from my point of view i have plenty of happy customers for whom ive specified the system.
If you could use 90% less fuel to heat your house... wouldn't you do it too?

[James T aka Mr. James T]

just at the stage where ive got to decide which route to take and from a long term point of view the dcv seems less complicated.
what company do you work with

[sydthebeat]

im an architectural technician, i dont work with any HRV company... i specify build elements and technical installations.

[BryanF]

Originally Posted by James T aka Mr. James T

just at the stage where ive got to decide which route to take and from a long term point of view the dcv seems less complicated.
what company do you work with

less complicated, but will you not be using your heating more than if you installed MVHR? perhaps you've a free fuel source sorted?
(btw I'm an arch tech also)
here's something I prepared earlier
http://www.boards.ie/vbulletin/showp...2&postcount=12

why not calculate your required l/s and then the dwellings air-change over a day of heating?
http://www.environ.ie/en/Publication...ad,1647,en.pdf

http://www.aecb.net/PDFs/9Jan2009_MVHR_Final-2.pdf

[James T aka Mr. James T]

i am not an architect but i can understand the principle of MHRV it is just long term is all i am thinking about.
Air quality is important but will HRV still give me good air in 10 years or 20 years of duct use that is all.
i do understand the changing filters maintenance regime but the pipes are going to be manky from years of use and your supply air has to come through these

[BryanF]

yes and so you should think about the long term, thats why the archs on this forum bang on about construction drawings and taking the time to plan the ventilation layouts at as earlier a stage as possible, preferable before going to site..
re manky pipes - you install smooth bore rigid pipes and grills/terminals etc (arranged for future access to allow for cleaning)
there will be components in the MVHR unit to be changed, so above that's why i recommend the larger European manufacturers that have been around for yonks and will be around at that this future replacement stage.

so think about your pipe runs, have you allowed adequate space? can the main legs be arranged in a storage press for instance to allow for future maintenance etc... can the unit be within the thermal envolpe and so on

if your not bothered with mvhr, before your move forward consider my question above. calculate how much it will cost to heat your building from say 0degs to 20degs and keep it there for a 24 hour period then ask yourself what your expected air-changes per hour will be? the current regs stipulates a pass rate of 7 air changes per hour. will you get to 3,2,1, passive levels? and if you got to say 2ACH how much better would it be if you were recycling say 70% of that heat? and how long would it take to pay back your initial investment?

i wish you well with whatever you decide, but please come back and let us know how your getting on. seriously, a bit of data feedback on mvhr and dcmev systems would be welcome

[fclauson]

Originally Posted by James T aka Mr. James T

... but the pipes are going to be manky from years of use and your supply air has to come through these

My view is that my chimney needs sweeping, my boiler servicing and my well pump filter will need clearning

so I am assuming my duct work will also have some form of maintenance cycle

[lkdsl]

We got MVHR as a retrofit and the results are wonderful. The one we got is Dutch (it seems to be standard in Holland). There are no joins in the ducts, single runs, wide turns, so no corners. The ducting is smooth on the inside with an antibacterial coating. Apparently, it shouldn't need cleaning but if it does, there is a brush thingy that fits the shape of the ducts.

We got it fitted by a local guy (who I used to work with). It's been in for 18 months - clean filters every 3 months; replace after a year. Not sure whether to post the name here, but if you want it, let me know.

[esox28]

lksd

can you pm the make please

regards

[James T aka Mr. James T]

Sure. If you can pm me details thanks

[tred]

Originally Posted by James T aka Mr. James T

Sure. If you can pm me details thanks

One thing to compare demand controlled versus heat recovery is mainmtenance and power consumption. the heat recovery unit uses more power and also has at least a yearly cost of filter change. These filters can be expensive. Cost that into your solution, over 25 years as well. Also, there is maintenance of the air supply vent pipes keeping them clean.

[lkdsl]

FYI of those considering MVHR, the on-going costs in our case are as follows.
At the lowest setting (which is what is suitable for our house) energy consumption is about 30W. The filters are 30 to 80 euros (once a year). It depends where you buy them and how fine a mesh you want. Cleaning the supply vent pipes is very easy in the case of the system we use - they are very short. From the outside to the unit is less than 1 metre and the pipes are easily removed should we want to clean them.