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View Full Version : Customer wants quiet system for bedroom (60mē)?


expat
09-10-2007, 10:35 PM
I've looked at loads of makes and can only settle on the Mitsi heavy range for their low db levels. But now I'm thinking, how quiet does it need to be for you to sleep?

To explain it's a 60mē room in a loft. There is good modern polystyrene insulation under the terracota tiles maybe 16cm thick and good insulation in the walls (rock wool type, 10cm). The exterieur walls are 27cm breeze blocks. There is a lot of south facing maconery including roof.

Calculating as by the rules of thumb I come up with a budget busting system at somewhere around 8kw but I'm thinking if he only wants to sleep there maybe he could get away with a smaller system as he will not be fighting against the sun or new air intake during the night.

This is a little long winded I'm sorry, but I've been through the searches so many times now and I can't come up with anything useful, as many others seem to be treating sizing with a yard stick. No offense meant because this usually works when you just want to make sure it's cold enough but it doesn't when you are talking about a large room where the install price will quickly get out of hand.

The system I looked at is a Mitsi Heavy SRK71ZE, pumps 8kw and runs at an amazing 26db on low speed, but we're at 3760 euros ex vat and ex my install. And at that price I think it will be ex my contract!

Anyone got any advice?
expat
09-10-2007, 10:43 PM
Goo on, answer, I'll tickle yu scales, add yu to my buddy list!
The Viking
09-10-2007, 10:50 PM
When it comes to the heat load, ask the customer if he needs the room at a steady temp (say 22 Degrees C) or if what he really is after is a slightly cooler room than what he's currently got (well, in summer time).
This can make a huge difference in capacity needed.

Re noise levels, If they really wants it quiet, then you can't beat a ducted system.
But be aware of the quoted noise levels, it's a dark art form and all the manufacturers are measuring in different ways.....
expat
09-10-2007, 11:12 PM
Re noise levels, If they really wants it quiet, then you can't beat a ducted system.
But be aware of the quoted noise levels, it's a dark art form and all the manufacturers are measuring in different ways.....


Ok mate, I hear what you're saying. I fitted a 3.5kw and a 2.5kw Mitsi elec in someones house not long ago and I have to say on low speed you couldn't hear them. Both units claimed 22db.

It seems that all of my catalogues say the sound test was taken at 1m from the unit. But then there are decibel metres and there are decibel meters just as there are leak detecters and leak detectres!

BTW how's it with you and her indoors. Mine is still not speaking to me since I went to the bar on Saturday night to see the match with the boys:rolleyes:
al
10-10-2007, 12:04 AM
expat

I'd chance a 6kw, we've a hitachi rac25 installed in the bedroom and on sleep mode its inaudible, esp with my snoring!!

Al
The Viking
10-10-2007, 01:40 AM
But then there are decibel metres and there are decibel meters just as there are leak detecters and leak detectres!

BTW how's it with you and her indoors. Mine is still not speaking to me since I went to the bar on Saturday night to see the match with the boys:rolleyes:

Ahh, the lovely miss X.....

The biggest difference with all noise metering is what type of room it was done in, the extremes would be metallic walls versus "coned" rubber walls.
I once were in a room where they tested the acoustics for jet engines, if your mate were in there standing 2 meters away and screaming his head off, you could bearly hear it (even with all their machinery turned off and the room quiet). The sound technician's explanation was that in that room, for every straight/physical meter the sound had to travel 50 meters:confused:.
expat
10-10-2007, 11:48 PM
Thanks Al, but the RAS 25 running at an inaudible 20db isn't going to cut it with only 3.1kw max.

I think I'm going for the Mitsubishi heavy SRK50 as it delivers up to 5.3kw and has a slow speed sound of 23db.

This should get the quote back into an acceptable perameter.
expat
10-10-2007, 11:51 PM
Viking, that's interesting stuff you said about sound, I will keep it in mind.

Sound has trouble going round corners!
frank
11-10-2007, 12:45 PM
Sound has trouble going round corners!
But it travels along FLANKING PATHS really good! ;)
expat
11-10-2007, 09:42 PM
What's a FLANKING PATH when it's at home?

Much more importantly what's KEO? I mean you had Speckled Hen, Worthingtons..., I was going to carry on the list but it's been so long I contritely admit...........I've forgotten them:o

Still remember the reckless nights on Abbot though!
frank
11-10-2007, 11:53 PM
What's a FLANKING PATH when it's at home?

Much more importantly what's KEO? I mean you had Speckled Hen, Worthingtons..., I was going to carry on the list but it's been so long I contritely admit...........I've forgotten them:o

Still remember the reckless nights on Abbot though!
Do a Google search on Flanking paths as there are lots of different sites willing to explain the term.

As for KEO, well have a read here (http://www.atheneeimporters.com/keo.htm).