I am looking at getting this this A/C system installed.
I am just finishing a major renovation on a 1957 hydronically heated home. I do have to still get an HRV system installed to meet current building code ventilation requirements and might as well provide air conditioning while I am at it. My options are to get an ordinary HRV supplemented with wall mounted AC in the rooms needed (with a central condensing unit on the exterior) or to get an HRV with an air handler (and increased duct size) to accommodate central A/C.
The advantages of the wall mount system seem to be efficiency, quietness, supplementary heat and cooling delivered to where it is most required. The main disadvantage I see is bulky units on the ceiling/walls. The advantages of the central system is mainly no wall units, but with the need to try to manage cooling being delivered to a basement that does not need it.
Anybody with experience with the wall mounted units?
We have a similar unit in our basement, it runs great, is quiet and doesn’t take up a window. The only downside is that it does take up some space in you yard. That style of AC is the standard in most of the rest of the world.
It is not a big step to put dampers in HVAC ducting and allow zoned control. Any house of more than one story and more than about 1000 square feet should have at least two zones for efficiency. So “cooling a basement that doesn’t need it” is avoidable.
One forum is available to non-HVAC professionals.
They view it as a way of finding customers. Act accordingly.
You will initially get a ‘ask your local HVAC pro’. If so, push back with ‘wantto know enough to speak intelligently’.
Ask for info and opinions, not ‘how’.
I’ve installed several. You need the same level of skill to install a split ductless system as to replace a standard compressor and a-coil. If you do it, always put in a heat pump unit as the price difference is negligible. My brother sells and installs them, and has told me new units are as efficient as 33 SEER, and can heat and cool 300+ sq feet of living area with 110 volt,15 amp circuit.
In almost all cases, the external unit can be mounted on an exterior wall. You run AC to that unit, two copper lines and a low voltage fan and control line runs into the interior unit from external. They do a good job of moving and filtering air, with fan blades that move both sideways and vertically.
You have to pull a vacuum and adjust the coolant levels - two jobs that require at least $500 worth of specialized tools. It’s really not a job fpr a hobbyist, unless you plan to install a dozen of them.
Mitsubishi has some different head units, including ones that look like a picture frame, but they are at the high end of the price range.
10 years ago, I saw ads for companies which were aiming for the DIY market - you tell them which unit you want and the distance from the compressor to the head - they supplied the compressor pre-charged with the proper amount of refrigerant in the compressor and a lineset pre-cut to the proper length and flanged.
Te DIYer would connect the lineset and open the manifold to charge the system.
No need to buy refrigerant or pull a vacuum.
The HVACTalk people really, really did not like them.
As I recently found out/confirmed, HVAC people as a whole make cardiologists look like humble salt-of-the-earth plain folks.
(I had problems with the low-voltage portion of my AC system, a subsystem I am more than competent to diagnose and repair. I ran into unbelievable problems getting simple things like a replacement transformer because the field here is divided into contractors who only do the work themselves, and wholesale providers who only sell to licensed HVAC contactors… and just who did I think I was, trying to buy HVAC parts as Joe Q. Public?)
Thank you for the replies. To clarify, I will be having a professional contractor that I regularly work with do the install. I am a fairly highly skilled residential carpenter and there is lots I can do to a professional standard, but this is not one of them with the time I have available to me.
I am leaning towards the central system with the HRV + air handler and bigger duct work now. Meanwhile the contractor has informed me that they are not going to be able to get a crew over before my deadline to move in, so there is no rush on the decision now.
This is definitely one of the issues that presents itself. I have a good enough relationship with my plumber that I could probably get anything I needed through him as a mechanical contractor at cost. Even as a builder though it is hard or impossible to get a lot of HVAC materials. They just won’t sell to anyone who isn’t a mechanical contractor.
You know you have to be licensed to buy some coolants, don’t you?
I’ve never, *ever *encountered anyone asking for proof that I’m a mechanical contractor. What they don’t want, and I can’t blame them, is to sell parts to someone who will then expect that this $5 part automatically comes with several hundred dollars worth of support. If you’re really skilled, and are fixing something like replacing a starting capacitor, everyone I’ve ever met in the business is more than happy to sell me what I need. But, they want to make sure that I really know what the hell I’m doing.