HVAC
I need some advice. We are soon to begin reno. of a 5 unit, center stair, frame building. Desiring a high efficiency HVAC system, we chose Daikin VRV air source heat pumps. Seemed like a real good compromise (geothermal was our original idea) providing both heating and cooling with a single unit and still not…
I need some advice. We are soon to begin reno. of a 5 unit, center stair, frame building. Desiring a high efficiency HVAC system, we chose Daikin VRV air source heat pumps. Seemed like a real good compromise (geothermal was our original idea) providing both heating and cooling with a single unit and still not relying on a combustible heat source (at least not on site). Although a compromise, it aint cheap, and with the economy doing what its doing we are now seriously considering another redesign. And so we get to my point, any opinions on PTAC’s as a much, much, much less expensive alternative?
hey eman, though not contemporaries, we might just be kindred.
By the way, he cant sing. His genius is makin’ us believe he can.
wow a reference to “zen and the art of motorcycle maintenance”.. i suddenly feel younger, kind of like when my girlfriend tries to explain to my 16 year old daughter why 52 year old white guys think bob dylan can sing…lol
BJ, I don’t follow your logic one therm. Are you suggesting that a more costly system is less efficient because it costs more? Generally speaking higher efficiency and higher quality products cost more, true. This rarely takes into account the secondary and tertiary cost/consequences associated with the less expensive product, though. Environmental impact and long term viability are just two of the many factors that are generally not considered by the consumer when making a choice. Robert Pirsig understood this. It’s a question of quality. Quality products, quality experiences, and a quality of life. This is why I am laboring over the decision of what to do for HVAC in a seemingly insignificant 5 unit building. Truth is, nothing is insignificant.
my understanding of the subject is:
directly or indirectly your heating cost is attached to burning oil. So if you will pay twice less for electricity to run a heat pump it means somewhere people spend twice less oil to produce electricity then you would burn in furnace.
Same simple arithmetic applys to the cost of the system: more expencive systems require more energy and resources to be produced.
Also, it’s more expensive but there is a Mitsubishi unit which looks like a large ceiling register but needs to be installed in a 12-18″ ceiling cavity (the works are up there). If you have an open layout, one unit could service the whole parlor floor. Again, have never seen one installed—does anyone have this?
While I can’t speak from experience, I think a suitably designed bookcase can have a niche for a Mitsubishi indoor unit and it would be palatable. There’s also the ArtCool which can look like a flat silver plate but then I’ve never actually seen one.
I’m very impressed with the Dalkin-5deg spec. I could not find that on their website. Given NYC conditions, that’s more than acceptable.
The Daikin units are the most efficient on the market. They are able to extract heat from the air down to 5 degrees.
Once again though, they cost a fortune. A HE condensing boiler coupled with cooling via split units might be a solution, but we are then talking about 2 separate mechanical systems as opposed to the air source heat pumps or PTAC’s which are single systems providing both. The aesthetic limitations imposed by the PTAC on the exterior is not desirable, but also, not insurmountable. This building is not a brownstone. As for the interior; the PTAC under the window is probably going to easier to deal with than the “big plastic monster” on the wall or ceiling. Having said that, the ceilings do average 10 ft. The apartments are all rentals and relatively small @ about 500sf. Suburban brand PTAC’s burn at 80-80%. Has anyone any experience with these?
got to agree with cmu…but man i hate those ductless systems …while efficient you end up with a big ugly plastic monster hanging from the ceiling…you can get away with that in a loft with 12-15 ft ceilings…but in a brownstone? barf barf
No comparison on cooling effcy, PTACs are lower (and many would think, ugly.)
otoh, air-source heat pumps give up at 25-30deg or so and use their backup electric heaters, so the coldest time of the year, you’ll pay 5x for heat (I may be off in details, but that’s how they work.) Check this out carefully before committing.
Best bang for buck is HE condensing furnace driving wall mounted radiators, and, if you really need a/c, ductless systems. Won’t comment on aesthetics, tho.