HVAC in house without ductwork

11 Replies

Hi All! 

Maybe you can help me with an important decision about HVAC for a home we just bought. It is a 1950's ranch in CA near Sacramento. Currently it has no cooling system and the gas furnace only serves about half of the house and the ducting associated with it will most likely need to be removed. The reason the ductwork will likely need to be removed is that it was installed in an unpermited, poorly built, "attic" that was created by building an entire new roof with new trusses/rafters over the original one. The original roof was a typical ranch roof - long and low. The slope is slightly less than 3/12. The house has vaulted ceilings which we want to keep and a slab foundation so if we go back to the original roof there won't be any easy way to add ductwork.

The only option I can think of for adding both heating and cooling is the mini (multi?) split ductless system but I know very little about them.Some of the questions I have are:

1. Am I correct that a mini/multi split system can provide both heating and cooling?

2.Are these systems designed to only provide additional heating/cooling or can they handle the job on their own? The climate here is - average highs in the summer are 80's and 90's with some 100+ days. The average low in the winter is above freezing, but occasionally could go below freezing.

3. Is the difference between mini and multi split that the mini is designed to handle just one room or zone? and the multi will handle numerous zones?

4. Do they work ok in very open spaces? The living room, dining room, kitchen and breakfast nook are all 1 open space with a vaulted ceiling.

5. Are there other questions I haven't thought of to ask?  

We are planning to live in this house at least a couple of years while we continue to remodel it and so want to be sure it will be comfortable.  

@Debra R. ,

I like these systems and they work very well.  They do provide heating and cooling.  You will not need a standard HVAC system to assist these as long as you get a big enough system to handle all of the rooms in your house.  You may need two systems.  Each system has between 1 and 4 "heads" (inside units) and are installed by drilling a 3" hole through the wall and the head installed/connected to it.

You can run each head in every room individually which is a big plus.  You won't have to heat or cool every room in the house.  For big rooms you may need two heads to heat or cool and then one for each bedroom or small room.

Take a look at Home Depot online or Google them.  There are many brands and sizes so the actual cost will depend on the sized of your house and how many units and heads are needed.  They are energy efficient and again, you don't need to heat or cool the whole house.

I have been looking at them for awhile now to put into a fourplex I own downtown and we use them in our offices where I work.

There are always discounts and show specials if you check out the home shows either at Cal Expo or the convention center.  Home Depot and I'm sure other retailers or HVAC installers should be willing to give you a free estimate.

I agree with Parker and also fujitsu has  a heat pump system that has one outdoor unit with ability to have multiple indoor units/zones. I have installed the Fujitsu systems multiple times and haven't had any complaints over at least 8yrs. Also the units or installed in northern CA 

Mini Splits are a great option.

1) Yes, mini splits heat and cool.

2) Mini splits can handle a very wide range of temperature conditions.

3-4) Depends on your personal needs.  If you want more options for climate control room to room say in your bedroom additional heads are needed. However depending on the load of your house you may be able to get away with one head, especially with a open floor plan.

4) You need to talk to a installer/supplier to see how many BTUs it would require to adequately supply your home and see what your options are. 

We are renovating a house in Austin that did not have A/C.  I looked at mini systems and for our 1,000 sf house was told I would spend around $20k.  It was my first exposure to ductless systems but that knocked me over.

I was told the system would work well here (summer highs in the 90s).  That price was a show stopper.

We are adding central air and running duct.  The whole house is shiplap (tongue and groove) so there will be a good bit of cutting ahead.  We do have good attic access.

I am still spending ~$9k for the central air, condensing unit, ductwork, condensate drains, and two exhaust fans for the bathrooms.  I had budgeted for about 2/3 of that cost.  At least I carried a decent contingency on the project, so my budget is till intact.

You can get a 2 ton ductless heat pump on ebay for about $900 which is designed for over 1000 square feet and it doesn't take a genius to install them.  You can also find 1 ton portable heat pumps online for $200-300 which are designed to heat and cool 400-500 square feet.  I picked up a used one today for $100.  They a pretty easy to install.  The biggest hurdle is setting up a hose to drain the condensation so that you don't have to keep emptying the tank.  I use one inch outer diameter vinyl hosing, a hose clamp and a 1" auger bit to accomplish this.

Debra is your slab intact?

I've never been a fan of a unit that does both heating and cooling, if you were to repour your slab you might think about radiant heat and then do the ductless A/Cs? just a thought.

@Debra R. , @Hugh Ayles is right. in consideration of resale, you want to install a professional heating/cooling system. For a multi ductless system, you will most likely pay twice as much as a traditional central HVAC system.

Have you considered adding decorative soffits to your ceilings that the ductwork could run through? Like mentioned earlier, you really only need 12" of cavity space to run some flex duct. Sounds like you are tearing out the old ceiling and rebuilding, anyways? Why not add space for the ductwork within your new vaulted ceiling?

Hmmm, not sure why I didn't get notified of the Oct 1 posts. Sorry for the late reply.

@Hugh Ayles , @Jassem A. , @Marc Dupuis , @Jesse Hinaman@John Weidner

 A bit more info - I've had 3 roofers say that it would be cheaper to remove the second roof/attic than try to correct the framing/ fix the dry rot/ re - shingle and permit. 

When I return the house to the original roof I'll save money roofing wise and make the house look better by sticking with the ranch style - long and low.  Once I do return it to the original roof there won't be any attic.  With a slab foundation that doesn't need removal, there's no crawlspace.  

When you're inside the house and looking up you see the vaulted ceiling in every original room except the bathroom.  That ceiling is tongue and groove with exposed rafters and a beam that spans the length of the house.  The roof is in contact with the tongue and groove.  So there's no attic and not even a little bit of space to put ducts.  I could add a dropped ceiling, but I'm trying to keep the ranch look as much as possible and the vaulted ceiling is a huge part of it. The ceiling looks similar to  this one -  


Once the original roof is visible it will look similar to this-

https://www.flickr.com/photos/[email protected]/1427831...

Same shape of house, carport in the same spot except that mine is a smaller carport and has been converted to living area.  

Does anyone have any ideas for both Heating and AC other than mini/multi split ductless that will suit this situation?