AC options for house with steam heat

JackFre

This is a perfect application for a mini-split...in my self serving humble opinion. I represent Fujitsu in New England. Choices abound and it is the highest efficiency and best technology and least disruptive install in A/C today. Inverter based, so modulating/variable speed compressor/fans. You say the first floor is fairly open. Generally speaking...put an evaporator at opposite ends of the first floor. Given the long run times available with variable speed equipment the air spaces will communicate nicely. Our 24RMLQ (single outside unit with two interior evaporators) would give two 12k evaporators each capable of modulating from 5500-13,600 btu. Given that they moulate, they will in most cases operate at lower speeds, so will be very quiet, dehumidify very well and size themselves to the demand. 16.5 seer. Very compact equipment. Also, they are heat pump so in the Sept/Oct, April/May period you can handle the heat efficiently (EER 10.4/11.9). Don't run your central heat until it gets cold. Otherwise it is way oversized and inefficient. Use all available equipment options for a better "seasonal" efficiency.

Upstairs can be done in basically the same way but layout is obviously more difficult due to the configuration of bedrooms. Our multi-zone systems can be done in 3,000 btu increments from 18-36kbtu. Your and your installing contractors choice depending upon need. www.fujitsugeneral.com

Joe Chan

AC options for house with steam heat

We live in a 1933 Tudor with steam heat in the Boston area for a few years with only an old in-wall AC in one room. It wasn't much of a problem when both of us were working. But now that the kids are here and my wife became a stay at home mom, she has been advising me of the impending doom for the lack of cool air in the summer for the past few years . Now that big old AC is not looking like it'll last much longer (it's probably installed around 1980), I'm looking into some AC options.

Some details about our house. It's a two stories house with brick exterior at the first level, and stucco at the second, around 2500 sq ft, a fairly typical boxy colonial layout. The first level (~1200 sq ft) has the dining room, living room, kitchen, and family room in the four quadrants, plus a small half bath. On the second level are 4 bedrooms plus a bath (~800 sq ft). There is a walk up attic that is unfinished, vented, and the attic floor insulated with ~1ft of celloluse. The basement has a 250 sq ft finished bedroom and bath at the back of the house, with full window to the back yard (the house is on a hill).

All the room in the first floor are opened to each other. The back of the house are the family room and the kitchen, linked together with a large pair of french doors, and now "cooled" by that old Friedriech (this is the hot side, getting about 6-8hr of direct sun a day). The front part of the house--the living and dining rooms--is the penalty box in the summer (they are also connected by a wide doorway, this is the shaded side, hardly get any directly sun). The front and back half of the first floor are connected by three normal size doors. The stairs to the second floor is in between the living and dining rooms.

Our primary concern is how to cool the first floor. We can live with having window units for individual bedrooms upstairs. So options I considered are:

1. put a couple of window units in the first floor and let them run at the same time with the one (the wife is threatening to this if I do nothing).

2. Put in one of those ductless system with multiple air handlers for the first floor. My family in Asia has one of these, but their apartment is only 700 sq ft.

3. Bite the bullet and go for central AC, probably a high velocity system as we have no room at all for those big ducts.

Besides the obvious difference in installation cost, my concern for central AC is that it doesn't look like there is a way to zone the two floors separately. I'd hate to spend 50% of the cost on cooling the first floor for 8hrs every night. (We don't care about the basement bedroom, it's just a guest room. We just won't have guests for the summer )

So if you are still with me, here are my questions:

- how feasible is to just cool the first floor, and what kind of system will be suitable to do so?
- Is it possible to zone central AC at all? If that's possible, and we have one zone per floor, would that be effective? The stairs are wide open, so would the cold air just all sinks to the first floor?
- Roughly what is the cost of operating a central AC system around the Boston area (the wall only has 1" wood insulation boards and the plaster walls)? A next door neighbor once told me he had a ~$1000 bill in one bad month (granted his unit was installed by Sears in early 1970s).
- Roughly what is the cost of installing a high velocity AC system for a house our size? (Just looking for ballpark figures here, e.g.$10K, $20K, $50K?)
- What is a good place to look for contractors? Any kind of certifications, buzz words to look for?

Thanks for your patience.

Joe Chan

AC options for house with steam heat

We live in a 1933 Tudor with steam heat in the Boston area for a few years with only an old in-wall AC in one room. It wasn't much of a problem when both of us were working. But now that the kids are here and my wife became a stay at home mom, she has been advising me of the impending doom for the lack of cool air in the summer for the past few years. Now that big old AC is not looking like it'll last much longer (it's probably installed around 1980), I'm looking into some AC options.

Some details about our house. It's a two stories house with brick exterior at the first level, and stucco at the second, around 2500 sq ft, a fairly typical boxy colonial layout. The first level (~1200 sq ft) has the dining room, living room, kitchen, and family room in the four quadrants, plus a small half bath. On the second level are 4 bedrooms plus a bath (~800 sq ft). There is a walk up attic that is unfinished, vented, and the attic floor insulated with ~1ft of celloluse. The basement has a 250 sq ft finished bedroom and bath at the back of the house, with full window to the back yard (the house is on a hill).

All the room in the first floor are opened to each other. The back of the house are the family room and the kitchen, linked together with a large pair of french doors, and now "cooled" by that old Friedriech (this is the hot side, getting about 6-8hr of direct sun a day). The front part of the house--the living and dining rooms--is the penalty box in the summer (they are also connected by a wide doorway, this is the shaded side, hardly get any directly sun). The front and back half of the first floor are connected by three normal size doors. The stairs to the second floor is in between the living and dining rooms.

Our primary concern is how to cool the first floor. We can live with having window units for individual bedrooms upstairs. So options I considered are:

1. put a couple of window units in the first floor and let them run at the same time with the one (the wife is threatening to this if I do nothing).

2. Put in one of those ductless system with multiple air handlers for the first floor. My family in Asia has one of these, but their apartment is only 700 sq ft.

3. Bite the bullet and go for central AC, probably a high velocity system as we have no room at all for those big ducts.

Besides the obvious difference in installation cost, my concern for central AC is that it doesn't look like there is a way to zone the two floors separately. I'd hate to spend 50% of the cost on cooling the first floor for 8hrs every night. (We don't care about the basement bedroom, it's just a guest room. We just won't have guests for the summer )

So if you are still with me, here are my questions:

- how feasible is to just cool the first floor, and what kind of system will be suitable to do so?
- Is it possible to zone central AC at all? If that's possible, and we have one zone per floor, would that be effective? The stairs are wide open, so would the cold air just all sinks to the first floor?
- Roughly what is the cost of operating a central AC system around the Boston area (the wall only has 1" wood insulation boards and the plaster walls)? A next door neighbor once told me he had a ~$1000 bill in one bad month (granted his unit was installed by Sears in early 1970s).
- Roughly what is the cost of installing a high velocity AC system for a house our size? (Just looking for ballpark figures here, e.g.$10K, $20K, $50K?)
- What is a good place to look for contractors? Any kind of certifications, buzz words to look for?

Thanks for your patience.

jim lockard

Why not

The attic you say it is unfinished. The way we do older homes and we do alot of them is to oversize the second floor to cool the first. With 800 Square feet on the 2nd floor (do a heat loss/cooling gain) but I will put 21/2 to 3 tons of A/C in the attic with a dump zone or register over the stairway and a central return on the back of the hallway. Best Wishes J.Lockard

john_27

also, put an awning on your sunny side....it'l save you a boatload of money because it will eliminate radiant heat.....sort of like shade under a tree.....also, you can use reflective foil backed insulation in your attic to reduce the radiant gain there.....obviously, geothermal cooling would be your best solution...do a web search and see if anyone is close to you...if this isn't a solution,check the Wall for posts using the "search" feature above...lots of good stuff on this site!

Techman

House AC

Hay Joe. Why not two seperate systems and include the basement living areas for dehumidifing reasons.2nd floor with returns from each room so the air stays up there?

Joe Chan

I haven't thought about that. So I need to install one handling in the attic, and one in the basement (or both in the attic)? Can they be fed through the same compressor?

Techman

Joe

Two seperate zones if it fits your application,the heat load is diferent in each floor,probably an air handler in the basement,duct work between floors eats up valule closet space.Soooooo,its your choice!Good Luck.

clammy

not for nothing

Not for nothing but i believe that doing 2 seperate systems and running them like when you go to sleep turn on the second floor unit and shut off the first floor is kinda a waste and you usually always end up loading your 2 nd floor unit with a high heat lose and you never seem to get the humidity out of the home you end up with a cool muggy home some what clammy.If the heat gain is not to high do yourself a real favor and install 1 properly sized unit to do the whole house .Make sure your second floor bed rooms have a return installed in each room besides a supply register this will help keep the rooms cool when the doors are shut andf also reduces the size of your main return grill to some thing that is not such a eyesore .I have removed many a/c in homes with the 1 st floor 2 nd floor approach that HO insisted the systems did not work why because they where doing just what you would like to turning one floor on while the other is off .If your home can be cooled with a single unit do it every home that i have done this in has had lower electric bills then all the previous years and not one complaint about the unit not cooling the home .The last one i did had 2 3ton units i removed them installed 1 5 ton unit and some 2 nd floor returns in the bedrooms and the HO was amazed at how well the house cools 1 stat keep it simple also his electric bill was on average 50 to 75 less then before and now he's comfortable .On another note also have a electricnic or better yet hepa type filteration system installed it will guarente that your indoor coil remains clean and working at maxium capacity .Peace and good luck clammy

Ted_13

High Velocity System

Joe have you looked into a High Velocity system? With a high velocity system the branch ducts are very small and can reach areas where conventional ducts would be trouble. Check out spacepak.com and unico.com

Dave_4

HV AC

We were in the same situation (North of Boston) and just recently (last week) bit the bullet and installed a HV Unico system for the house.

In our situation, we decided to install a unit to serve the 2nd and 3rd floors (single zone) and forego the 1st floor for now.

We have found that the 2nd and 3rd floor now stay comfortable and we do not appear to be losing massive amounts of cold air to the 1st floor. I actually wish we were losing some to it . We had also looked at a split-ductless, but did not want the unit(s) hanging on our walls in the house. As Jack mentions, a ductless option may be right for you depending on your needs. Where I used to live, 3-4 neighbors got a split-ductless unit to deal with a very hot attic room and they were all very pleased with it. In a split ductless system while the equipment is expensive, the installation is simple in comparison to a high-velocity.

We have no chase from the attic down to the first floor, plus balancing that many floors on a single zone system would have been a mess, so we decided that if we ever did the first floor, we would do it as its own system (either conventional since we have room for ducts in the basement or HV again).

We have had decent luck keeping the 2nd and 3rd floor balanced, although since heat rises and our attic is unvented and barely insulated, we did go for a few extra drops on the 3rd floor since the thermostat is located on the 2nd.

I haven't had the system long enough to know what the electricity cost will run, but it was well worth it from a comfort perspective. The house was uninhabitable in warm days last summer and we could feel a major difference during the last group of warm days we had.

We interviewed a decent number of Boston-area companies and finally picked one that was very responsive, had a great set of reference customers and we felt did the most thorough job analyzing our cooling needs to design a properly sized system. The installers were gentle on our old home and ceilings that we did not want destroyed.

I know it's against policy to speak prices on the board, but needless to say, prices keep going up and up as the raw components (metal, etc), gas prices, etc are socking all of us in the wallets.

If you want to write me offline, I'd be glad to provide the name of the Boston-area HV AC folks we ended up hiring after an extensive interview process as well as the name of our wonderful electricians (needed to provide electricity to the condenser outside, air handler inside and get the thermostat wire from the air handler to the right location).

This will be a very expensive investment in your home, be prepared for sticker shock, but it's well worth it for your poor wife who is stuck home melting all day long.