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  1. #1
    Join Date
    Oct 2007
    Posts
    6

    Default Type of A/C system

    Please help me.
    I am designing my next home, a small craftsman style bunglow. I will be building it myself as I had built my current home (a country victorian). My new home (as my existing home) will have in-floor radiant hot water heat. In my current home I went through the expense and hassel of also putting in duct-work for forced-air central air. I don't want to do that in my next home.
    I have seen two systems that I cannot find much information about, except "sales pitches" at manufaturer's websites. The high-velocity mini-duct system and the ductless mini-split system. I would only need to cool about 1200 square feet and all on one level. Could you please give me some advice on what you think would be the best route for my A/C?
    Also if you could either give me some suggestions on which manufaturer/system(s) are of better quality or lead me to where I could find some information on comparing systems I would greatly appriciate it.
    Thanks.
    Dayna

  2. #2
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,557

    Default Re: Type of A/C system

    Dayna,
    It would be helpful if we knew you location. Requirements for Death Valley would be differnet than for Main.
    The basic differance is that a high-velocity mini-duct system is basic the same as most central air units except it uses small ducts and a very high speed fan. All of these units I have seen were installed in the attic and the ducts feed out th ceiling. The ductless mini-split system is similar to a large window air conditioner except the only thing thru the wall is the pipes to and from the condensor which sits on the ground like a central air unit. These units do not have ducts going to other rooms.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  3. #3
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: Type of A/C system

    Dayna ,

    The mini split type A/C systems are really an alternative but similar to window A/C systems. They will only condition a particular room and not the hole living space unless it's one big room.

    If your new home will have separate rooms with walls and doors then you will need separate units for each room you wish to condition. They also require holes available to feed the lines from the outdoor condenser to the inside air handler.

    Having experience with these types of units the air handlers are noticeable in the living space , it's difficult to conceal them. Also placement of the air handler can be difficult so as not to be noisy and having cold air blowing on you directly.

    They certainly do work well for difficult retrofit applications.

    Here's a link to a product that I've had experience with : http://www.mitsubishielectric.ca/duc...A01-02H01.html

    Fortunately you have the opportunity to include a system into the building of your new home so the choice you would have is .... do you want these air handlers that are visible in your rooms or the less obtrusive central air system ?

    Cheers.

  4. #4
    Join Date
    Aug 2007
    Posts
    8

    Default Re: Type of A/C system

    Good advice so far....

    I differ from Canuk just slightly in opinion. Were I to do a small house again I would definately go with mini splits as my present 2200 sq ft one floor condo is set up with Mini's that serve the double purpose of cool and supplemental heat. The condo unit has radiator baseboard set to pump out 64 degrees from November to April, and the mini split heat pump allows a room to room adjustment for the heat load, even though sized for the cool load.

    The one drawback to the mini is they have this oscillator function and they do get noisy and bothersome after a season or two. I leave the oscillator function off and it works just fine without it.

    While they may have been originally designed for room by room, I have found that the hallways, baths, etc are all cooled nicely by natural draft, and if you don't have separate living/dining/kitchen, then one unit can easily do that room. For mine, there are 3 same sized units-one in each of the two bedrooms, one in a den that is bedroom sized; then a really big unit in the living/dining/kitchen area. the bedroom units are mounted about one foot lower than ceiling height and are maybe 3 feet long each. I'll bet too that since the inside units are not mounted on an outside wall, that if you would want to pocket the interior wall you could, and then only have the grill portion exposed and not the whole box.

    The great room, which is about 800 sq. all in by itself, unfortunatley wound up with what looks like an 11 cu.ft refrig sitting in the corner, but someone other than me decided on that as opposed to scattering other small units along the walls. It works...I no longer notice it is there.

    What I feel is the beauty of mini-splits is that they seem to have really quick response, meaning leave them set for like 80, and then when you walk into a room, simply have one of the remotes set for 75, give a tap and before you are even settled in it seems to arrive at the new temp. Another good feature is that they also have a max cool like your car. One of those sweltering humid days that drains you and you walk in? Walk in, tap the max button and in no time flat it can feel like a refrigerator and then simply tell it to go to 75 from there.

    They ain't cheap, it is about the most expensive solution out there, but I've been impressed with them. The control boxes are really cute too...sleep switches...timed pulse with fan only/ac toggle...lots of goodies because i have no wall mounted thermostats as such. All done by a remote control fob with a range so small, I can walk around with the fob and do each room since they are all on the same frequency and never interfere.

    Not sure about life as there are now 4 condensors outside instead of one...although quite smaller, but I figure failures will be 'soft' meaning one at a time so that won't be all bad.

  5. #5
    Join Date
    Oct 2007
    Posts
    6

    Question Re: Type of A/C system

    Thanks all for the responses so far...
    I live in Wisconsin, about an hour north of Madison (recently changed to a zone 5 -- at least for plantings... if that helps).
    To further help any of you give further input: in my new home I need to cool about 1200 sq ft on one floor. It will have a master suite, a good size kitchen with a breakfast bar (no room for a table or other eat-in area), and a combined living & dining room.
    Hopefully that helps with more advice from all of you.

    I have heard that the "attic" high velocity systems burn out because of the high heat in the attic. Has anyone else heard this or is this an urban myth?

    Also with the high velocity systems I heard that condensation builds up in the mini-ducts and "leaks" into the rooms. Anyone out there with one of these systems? Have you come across this problem?

    Also does anyone one have any advice on specific manufactures they prefer?

    Personally I like the idea of the mini-duct, high velocity system because I don't like the look of the duct-less units or the number of them I may need to purchase. However, I like the idea of no ducts at all too.

    Besides conventional forced air, high velocity, and ductless... are there any other options for cooling out there? I'm not just asking ways to better insulate or to install ceiling fans (you can already mark me checked for my current home and the one I'm going to build). And, if you so happen to know costs on anything, please include that knowledge too!

    Thanks
    Dayna

  6. #6
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,557

    Default Re: Type of A/C system

    Dayna,
    If you're planning a full basement then what not stick with traditional heating and HVAC with a small furnace room and a high efficiency furnace. You will have a lot more choices, a better chance of getting service when needed, and not have to craw around in an attic in July to change a filter.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  7. #7
    Join Date
    Oct 2007
    Posts
    6

    Smile Re: Type of A/C system **with radiant floors

    Thanks again for the continued replies.

    My basement in my new home will be completely below grade with two egress windows. The basement will be radiant in-floor hot water heated as will the main floor. The reason we are going with in-floor radiant heat is because there is no comparison. I, like my husband, grew up with forced air heat -- it is horrible dries your skin, causes static, and even the slight noise of the air blowing... but the biggest advantages of in-floor radiant heat is the comfort of heat, how it warms the floor and furniture (not just the air) and the cost (I am always cold and with forced air I ran the heat at about 74 with radiant I run it at about 68.... plus I have an open direct system which means the water comes into the house goes through the whole house filter and softener then into the in-floor pipes THEN into the 50 gallon water heater... it flushes the pipes every time I use a faucet. My one water heater supplies my potable water and my heat -- like I said cheap & efficient).

    My current home I went through putting in ducts because we were uncertain how excellent the radiant heat would be and had the option to go forced air PLUS we didn't know what to do about central air.... but now we'd never go to force air for heat but we are still stuck with the a/c problem.

    Does anyone have any information on the high velocity systems? Any manufactures they could suggest as reliable or that they had good luck with? OR any other suggestions for cooling?

    Thanks
    Dayna

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