Ductless mini-split in the basement?

I would get a experienced professional to design a functional system. Zones cost money.

All speculation is wasted until the heat load is secured and a professional specifies equipment based on local support.

All speculation is wasted until the heat load is secured and a professional specifies equipment based on local support.

I think it is important for homeowners to explore some options before taking the project to a "professional". I hope you realize that not many of them are as creative and skilled as you, BadgerBoilerMN.

No basement here - the downstairs slab on grade portion of the house is actually 3 bedrooms, 3 baths, laundry, entry and hallway.

Upstairs is the great room, living room, kitchen, dining - open concept...

The $25K does not include Warmboard...

Alright - how about thinking a bit out of the box then...as an alternative to hydronic radiant in floor heat

Use electric radiant panels, either in floor or in ceiling, in conjunction with a low temp mini split heat pump in the great room/living room area upstairs and then use electric radiant panels in the bedrooms to balance everything...

Don't know what the savings would be - but I think it would be pretty inexpensive to install and run.

My old home had electric radiant ceiling panels in every room, but the bathrooms which had electric radiant under tile heat panels (NuHeat, Warmly Yours etc...), and it was very inexpensive to heat the house...

Some floor panel systems are predictably expensive.
We manufacture and distribute RHT floor panel system. This lands on top of your sub floor, usually runs about $3.00-3.50 sq ft (pipe, manifolds, turns heat plates and site purchased 3/4 plywood infill). It is an alternative system, some call it a sandwich.
We can quote a package if your interested.
Dan

The $25K does not include Warmboard...

Eek!

Thanks ICF.

I appreciate the compliment, but the point is; if the DIY or informed homeowner finds a professional to do a heat load analysis he has an informed baseline from which to start. I eliminate 90% of the "options" e.g. radiant panels and fuel sources by the time I'm done with a heat load. Finding a contractor that can do a heat load is the best single qualifier for success.

Contractors and homeowners would benefit and are really just wasting time and money without a proper room-by-room heat load.

If electricity is cost effective (very rare) than an electric boiler with reset is the answer. Nothing can beat tube in a slab already paid for. I own a mini-split heat pump, but it is only used for cooling and dehumidifying.

I have been outside the box, fun but the weather can get to you.

Alright - how about thinking a bit out of the box then...as an alternative to hydronic radiant in floor heat

I think hydronic radiant is a natural for your lower floor slab. The question is, do you need radiant upstairs, and I don't think you do, especially because you have to go through the cost of adding radiant panels or mats and you will be operating at the (relatively inefficient) level of electric resistance heat for the whole place.

You could fire your hot water and hydronic heat with something gaseous and efficient and polish off the upstairs as it is inhabited with the efficiency of the ductless heat pump units.

if the DIY or informed homeowner finds a professional to do a heat load analysis he has an informed baseline from which to start

Well, it sounds good and I'm not arguing with that at all, but the problem is that I have heat load analyses (done by professionals) ranging from 38K to 101K for the same structure. What it looks like to me is that way more often than not, those professionals come up with a solution that represents an optimization of the profit/hassle equation for the contractor, not the homeowner. So, how does the homeowner know when they have a reliable analysis?

Posted By ICFHybrid on 11 Mar 2011 03:12 PM

Alright - how about thinking a bit out of the box then...as an alternative to hydronic radiant in floor heat

I think hydronic radiant is a natural for your lower floor slab. The question is, do you need radiant upstairs, and I don't think you do, especially because you have to go through the cost of adding radiant panels or mats and you will be operating at the (relatively inefficient) level of electric resistance heat for the whole place.

You could fire your hot water and hydronic heat with something gaseous and efficient and polish off the upstairs as it is inhabited with the efficiency of the ductless heat pump units.

I have been thinking of this route as well.  We will have a large open stairway that leads upstairs, so I think some of the heat will rise from and downstairs heat anyway.  Both the downstairs and upstairs heat loss is only 600 btu/h on the coldest planned day here anyway - which is very light load.  And we will have some solar heat gain passive gain based on some light design that way.

Was thinking a ducktless mini spit would be needed only when the days were very cold or just to bring the upstairs back to even with the whole house on cloudy and rainy days...

That would save the cost of Warmboard and additional tubing and 1 zone.  I just have to figure out how much that could save.

My other idea was a direct vent inwall natural gas fireplace to add some ambiance, but also to be the supplemental heat source for the upstairs.


Thanks for the suggestions - right now I am just seeing if there are some better choices than our first option...

You are in Santa Cruze Ca...Survived the Tsunami today? I heard the local surfers were out early, got to love SC...
Now,
2,700 square feet,If your heat load is 25 BTU sq ft.. strong for your area in general but for estimate, I think Dana is probably closer but for argument sake 25 BTUx 2,700 Sq ft= 67,500 BTU Tops. Real numbers for your area are probably closer to 18 BTU Sq Ft= 48,000 BTU or less.

load is on the domestic h20.
If you have a slab,insulate it, pipe it, you will never regret. it is a gentle warm floor, silent. You will want out door reset,
and as long as your running hydronic the upper platform is easy, keep your zones simple, one per floor.
Easy.

WarmBoard has a habit of zoning aggressively, zone per room. We like less and basic, but there are all different ways as you are getting from this thread, and most work and can be right! Even mine on occasion....
Dan

Posted By Blueridgecompany.com on 11 Mar 2011 04:09 PM
You are in Santa Cruze Ca...Survived the Tsunami today? I heard the local surfers were out early, got to love SC...
Now,
2,700 square feet,If your heat load is 25 BTU sq ft.. strong for your area in general but for estimate, I think Dana is probably closer but for argument sake 25 BTUx 2,700 Sq ft= 67,500 BTU Tops. Real numbers for your area are probably closer to 18 BTU Sq Ft= 48,000 BTU or less.

load is on the domestic h20.
If you have a slab,insulate it, pipe it, you will never regret. it is a gentle warm floor, silent. You will want out door reset,
and as long as your running hydronic the upper platform is easy, keep your zones simple, one per floor.
Easy.

WarmBoard has a habit of zoning aggressively, zone per room. We like less and basic, but there are all different ways as you are getting from this thread, and most work and can be right! Even mine on occasion....
Dan

Survived the tsunami so far - an hour ago they evacuated more area around our harbor (where the only damage has been).  Apparently there are more potential waves on the way. Wouldn't want to be a boat owner today or I would have taken my boat out early this morning - of course there was a whirpool out in the bay also at one point... I am sitting about 1/8 mile from the water, but there are 20ft cliffs and lots of road and houses in between - it would take a mighty big wave to do any damage here.

Thanks for the ideas.  I will work with Warmboard to keep it simple if an when that is our final solution - I am leaning that way, just want to shake out any other ideas and try to keep an open mind and educate myself as much as I can.

So you would do the entire downstairs as one zone under the slab?  Not break it into zones for each bedroom (3), hallway, MB?

We would need to see a plan to make any real design,

You can submit on on PDF to our site if you want,
Dan

Perhaps an independent RPA certified professional, using radiant specific software like Wrightsoft or product specific software such as Uponor/Wirsbo, Rehau or Viega. You might consider a designer without a warehouse full of product to specify the job and use the warehouse to supply the products you need, as that is their strong suit. Most heating contractors get their heat loads second hand, from their local suppliers, thus the creativity.

The SIP I am working on at the moment will have radiant slab lower, radiant ceiling upper and be driven by a 96% efficient condensing combi water heater providing space heating and domestic hot water in one 22" diameter foot print. I also use radiant wall panels for uppers as I did in my own retrofit home.

For light loads in the shoulder seasons the Mini-Split heat pumps is brilliant.

Any certified RPA trained professional can design a radiant floor heating system for any location in North America.

http://www.radiantpanelassociation.org/custom/directory/directory2.cfm

Two zones are simple but you would probably be better off with more. Look at each room and determine the flooring cover . For instance a bathroom with tile versus a bedroom with carpet should be seperated as different zones do to the R value of the carpet. It may cost a little more but the long term energy savings will justify the added expense.

So you would do the entire downstairs as one zone under the slab? Not break it into zones for each bedroom (3), hallway, MB?

Your climate is very mild. I would attempt to keep it simple. One zone. That will keep the costs down.

Have you checked into the cost of the warmboard alone on a sq ft basis versus regular subfloor?

We use Loop cad, loop lay out and heat loss. We charge for full heat loss.
Yes many zones are possible, just add to the project cost. Why not, many options to chose.
Yes we prefer to sell our product so specify it in our design and not our competitors products. We are not independent designers.
I like simple systems, The condensing tank is a good design though we do not offer those tanks. We will usually specify a wall mounted condensing boiler with built in on demand domestic H20. For larger residential and or larger domestic demands will use a side arm tank.
I like the additional solar domestic option with the side arm tanks by the way.
Lately we have been using a fair amount of TACO variable speed delta T pumps and zone valves.
Dan

An AO Smith Vertex 100 50 gal condensing hot water heater with side taps for radiant or hot water recirculating runs $2,000. That is one of the least expensive brands.

MA, what brand do you prefer?

You can have one zone but seperate circuits/loops for each room, and those can be controlled and adjusted.

-Rosalinda

Posted By ICFHybrid on 12 Mar 2011 12:08 PM

So you would do the entire downstairs as one zone under the slab? Not break it into zones for each bedroom (3), hallway, MB?

Your climate is very mild. I would attempt to keep it simple. One zone. That will keep the costs down.

Have you checked into the cost of the warmboard alone on a sq ft basis versus regular subfloor?

The warmboard alone is aprox $9k more than regular subfloor...

-----------------------

Ok so it seems as I get more quotes coming in, as well as good advice here I am starting to focus in on the best system for our home.

1. Use a Condensing Natural Water Heater like a AO Smith Vertex, Bradford White or Polaris...
2. Use a Ductless Mini-Split Heat Pump for upstairs heating, air cooling (limited use) dehumidifying etc...aprox 15-20,000btu size
3. Radiant in slab downstairs only - some heat will move upstairs through large open stairway, and passive solar will heat upstairs most days

This will save aprox $9,000 in Warmboard Cost, $5,000 in Radiant costs, $1500 in water heating costs - plus any additional labor... so around $15K savings

Seems like a pretty nice solution - Thanks to everyone's help here for guiding me - will update as things progress

Thanks for all of the responses , in my perception it somehow helped me in processing further with installing the same .








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