Thread Number: 50523
Hydronic Heat/Cool
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Post# 727350   1/13/2014 at 03:02 (1,260 days old) by jkbff (Gladstone, ND)        

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Ok, so I am looking at purchasing a home.. I am looking at purchasing a fixer upper.. Most of you are going to .. say I am stupid for wanting this, but .. it is what it is... I don't know what I am asking for so bear with me..

I want Water based heating and cooling.. I like the idea of individual temperature zones etc.. What I am asking is this.. Residentially, has it been done to take a High Efficiency Boiler and have it hooked to two buffer tanks, one tank being used for the house heating system and the other tank being used for the hot water supply for the plumbing?

The theory behind this is that the boiler for the heat system would be used all the time anyways, so why not use the high BTU to always have a hot water supply that never has to regenerate... I am understanding these boilers to be more powerful than a standard hot water heater so if the boiler makes the heat supply for both tanks, I'd never ever run out of heat for the house or heat for the water, correct?

Essentially, both tanks are hooked to the same supply lines that would be pumped through the boiler, but the energy is transferred to the water being held in the tank, so if ignition is called for one take, the thermal transfer would carry the heated supply to both tanks, both tanks would always be at the same temperature regardless of usage. Right? Also with that thermal transfer, say I wasn't using any hot water that day, but the radiant heat reached low temp in the buffer tank, since the water is being circulated through both tanks, there wouldn't be an over pressure on one tank from the heat cycle..

On the exact opposite of the spectrum, I'd want to use a heat pump/AC unit as a water chiller, and use water valves/solenoids that would allow each zone to switch over to cool mode and circulate cool water through and chill the house.. The radiators or whatever you wanna call the units in each room/zone would be fan blown so I could have zone heating / cooling.. There would be a third smaller tank to store the chilled water. I know there are condensation issues, I just need to find the kind of radiators that are made for both hot and cold water, and put drip pans in.

I plan on gutting the house, rewiring it and re plumbing it. I'd use pex tubing for the heat/cool system. I was thinking I could put the supply, return and drain lines all in a PVC pipe plumbed to each zone so when the system is on chill mode, incase the pipes sweat, they would sweat in the PVC and it would be carried down to a floor drain in the basement.

Also, each floor would have radiant heat as well so the bathroom floors would always be warm when needed.

Has any one gone this route? I don't want whole house HVAC because its moving the same stale are around and not individually zoned. It circulates odors and dust all through out the house. Also, I am going to have a rental in the basement. Independent climate for each zone seems like it would be cheaper this route in the long run instead of several split systems. Split systems have such a high up front cost, plus the energy cost. Also, it would be something that I could maintain my self since it truly is just water being circulated.

Plus it seems more feasible to do it this way instead of re-ducting the entire house. I wouldn't have to worry about energy loss when the air gets to the third level, and the comfort options seem to be better. Also, with everything having a zone and a coil of some sort, having make up air brought into the house when I install my exhaust hood would be easier to temper because I'd just add a radiator coil or two into the makeup duct instead of having another expensive burner/chiller installed.

This is all, of course, if I am understanding that the water used from the boiler that is circulated into the buffer tanks never actually mixes with the water that is in the tanks.. I have it in my mind that this technically would be 3 closed water systems, meaning the water for the house supply tank would never mix with the heated water from the boiler and the water in the hydronic heat/chill would never mix with the water in the boiler. If the boiler actually physically circulates the water from the buffer tanks, then back to the drawing board.

Thoughts, opinions?

Post# 727353 , Reply# 1   1/13/2014 at 04:26 (1,260 days old) by jkbff (Gladstone, ND)        

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I'm guessing as far as the hot side goes, I wanna go with HTP's Versa-Hydro. Now I'd just have to figure out the cooling side.

Post# 727472 , Reply# 2   1/13/2014 at 15:31 (1,259 days old) by brisnat81 (Brisbane Australia)        

With the cooling side, have you had any thoughts about how to handle the condensation that will form on the radiators?

They'll basically end up dripping wet as the humidity condenses on them.

Post# 727504 , Reply# 3   1/13/2014 at 17:05 (1,259 days old) by cuffs054 (GA)        

Like your idea and hope it comes together. Neighbor in FL (1957) had an interesting system in their house. Each room had finned piping near the ceiling hidden by cornice. It used hot water for heat, chilled for cooling. Unfortunently with no fan the cooling sucked and condensate would run down the walls.
Many older large apt. building have a system as your described. "Three Pipe System" one for hot, one for chilled and one return. On a small scale like a home with individual themos, keeping the chiller happy on light demands may be a problem.

Post# 727680 , Reply# 4   1/14/2014 at 13:03 (1,259 days old) by Davey7 (Chicago)        

I don't believe that radiant cooling is done with conventional radiators but with large pipes or slabs and is probably cost-prohibitive for a single-family or even large scale residential. It'll require an experienced, professional heating engineer to design the cooling too.

You'll need to do heat loss calcs for the entire house if you do radiant/hydronic heat. You'll probably want to pop over to Heating Help which will be able to give you more concrete answers.

From what you are describing you are planning a complicated system and you'll want to think about servicing and balancing, etc availability in your area. Good luck!

Post# 727683 , Reply# 5   1/14/2014 at 13:22 (1,259 days old) by wayupnorth (On a lake between Bangor and Bar Harbor)        

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I have never heard of hydronic cooling. The system you are refering to for heat sounds like what many around here use for their domestic hot water. A seperate circulator pumps the heated water from the boiler into a separate, super insulated tank with a coil running down the middle. It is much more efficient than a tankless coil in the boiler that cycles the burner on every time a faucet is opened. None of the boiler water is ever mixed with the domestic hot water in either system.

Post# 727686 , Reply# 6   1/14/2014 at 13:41 (1,259 days old) by kb0nes (Burnsville, MN)        

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My hunch is that there is a reason that hydronic cooling isn't often used.

The amount of heat that will transfer from the liquid to the air is based on the radiator surface area and the temperature differential between the air and water. With hydronic heating it is common place to have water temperatures 100 or more degrees (F) higher then the ambient air temp. The baseboards in my home will transfer ~850 BTU per foot under those conditions.

With cooling you can't get a temperature differential like that without using some kind of super cooled anti-freeze solution. So you would need LOTS of radiator area to transfer the heat into the system. Also if you can't get the water temperature low enough may be able to get cool but the dew point of the air will remain high, think cool and clammy.

The other big rub is condensation and how to deal with that. If you have an isolated evaporator in a forced air cooling system the condensate is concentrated into a small area and easily dealt with. Over a large distributed area condensation would be far harder to deal with.

Personally I'm a fan of hydronic heating. I like the evenness and ability to zone control etc. One big drawback though is that it doesn't move air around so air filtration is out of the question. If I were designing a home with a new hydronic heating system, I'd likely end up with a few small split system heat pumps to provide zoned cooling AND heating except for the dead of winter.

Post# 727688 , Reply# 7   1/14/2014 at 14:00 (1,259 days old) by whirlcool (Just North Of Houston, Texas)        

I've seen homes that have radiators have central air installed by running small air tubes in the walls to each room. They have a nozzles in the ceilings as outlets. The air that comes out is pretty cold and has good velocity. That may be another way to go.

Post# 727691 , Reply# 8   1/14/2014 at 14:25 (1,259 days old) by kb0nes (Burnsville, MN)        

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Allen, that is the system I have currently. High velocity 3" ducts that run through the attic to ceiling mounted vents. It was installed in 1991.

Prior to that the home had one BIG 24,000 BTU AC through the living room wall.

I wish the system were a heatpump, but there is concern with condensation inside the hoses that run through the unheated attic spaces. The outlets are plugged for the winter to prevent humid air ingress into the ducting.

Post# 892133 , Reply# 9   8/1/2016 at 22:44 (328 days old) by jkbff (Gladstone, ND)        

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I know I am digging up a very old thread, but I figure its better to use this one instead of making a new one.

I've moved into a 4 bed 3 bath unit with two upper levels and a tuck under garage. The unit is half of a duplex.

I am buying it from the owner, and am trying to figure out heating and cooling.

When the builder built the units, he ran out of money and didn't have central heat/cooling installed. The ducts are partially ran, but no equipment aside from baseboard electric heat. The unit was built in 2014/2015. Part of the failed oil-boom real estate crap.

Anyways, I am going to have a hood installed in the kitchen and an attic fan put in, but keep thinking about a water system.

What I am thinking is putting a fan-driven water to air heat exchange in each room built into the closets.

I am not looking for refrigeration as much as I'd be looking for temperature balance. The place has black steel roofing, and I've installed 12k 240v wall-mount ge ac's in each room. I built mounts for the windows so this is all temporary until I get everything figured out. I am trying to decide if I want to install mini-splits, or a trane XC95m/XV20i package. If I did the trane package, I wouldn't need this, but then the issue would be how to zone out the unit.

So the thought was to have three channels. One set runs outside, one set is internal and one set would go to a water heater. There would be three pumps, one for the outside coils, one for the water heater and one to circulate an internal channel.

What I am wanting to do is pull heat from inside to the outside on cooler nights. Have radiators or something outside with water circulating through, bringing the above ambient temps out, running the cooler water back in and circulating air through the coil inside. In the winter time, I figured I could have a GE 50 gallon GeoSpring water heater on the second channel and could circulate hot water through the exchange coils. The third channel would link all of the coils together, so I could do temp balancing. The idea behind the balancing would be that currently, I can only be in one room at a time and I live alone. There are 9 rooms I can be in (kitchen, bathrooms, garage and laundry room). If I am cooking in the kitchen, I could pull the heat out of the kitchen and pump it into the other rooms, or the garage or something...

The biggest reason behind this is my condensing miele dryer... Dear lord does it get hot in the laundry room without central air or a window....

But anyways, each room would have three pex lines ran and hidden in the crown molding. A feed, a return and a drain line. I would probably put two 24" exchange units in each room, some form of low-power consumption blower and a small pump to drain any condensate (if that would even happen). I don't expect the temps to go above 110 for the water, so I could probably use irrigation valves to do all of the switching. Each feed would have three valves merging to the one line and the same for the return. I'd use an automotive coolant to circulate, and keep the system sealed or at least have an air bleed off the water heater. I'd use a set of automotive radiators and cooling fans outside.

Ideally I'd pull the cool night temps in, get rid of the heat, and have it all accomplished with a series of low voltage pumps and fans. In the winter, I'd be able to have the outside channel pulling frigid temps in to cool the kitchen, or pull the heat from the kitchen and put it in the un-occupied rooms, have the hybrid water heater heating the coolant mixture and bringing a gentle heat into the rooms that call for heat.

I am not sure if I am explaining it properly, I'll have to upload my drawings...

And I know this is coming, why not open the windows? Well, the rooms that have ac have the windows blocked by the ac, and the house is in the middle of nowhere with train tracks less than half a football field from the front and a valley behind it. My allergies go haywire when I open the windows.

If anything, would a system made of various exchange coils and low-cost automotive radiators accomplish anything close to what I am looking for?

Post# 892140 , Reply# 10   8/1/2016 at 23:35 (328 days old) by thomasortega (Los Angeles - CA)        

Before one consider hydronic systems, spend some time to phone Mr James Moris, General Manager at Extended Stay America Frankford here in Dallas.

It will be something like: Hello Mr Morris, I want to know your opinion about hydron... (he won't let you finish the word)

That f-word (add at least other 5 adjectives or bad words) system is the worst (adjective or bad word) a son of a ... (add more four bad words) invented.

If you want, you can come here and take it for you. there are 180 something Bosch units plus the boiler, plus the chiller, plus miles of pipes... take everything with you for free. becaus that (6 bad words) is a (choose a horrible adjective)

Post# 892183 , Reply# 11   8/2/2016 at 08:53 (328 days old) by vacerator (Macomb, Michigan)        
Hot water heat

is the most comfortable and efficient, but if you want central air conditioning with it, you need to install it in the attic, and put in vents in your ceilings. Cold air drops, so it is also a more efficient way to cool a home. May not be an issue in N.D.

Post# 892276 , Reply# 12   8/2/2016 at 17:54 (327 days old) by CircleW (NE Cincinnati OH area)        

A.C. vents in the ceiling is fine, but I would never recommend putting the air handler/cooling coil in the attic.

My dad had Dunham-Bush SpacePak air conditioning installed in our house in the mid 70's, with the inside part in the attic. Everything was OK for about 15 yrs. or so, then the condensate pan rusted out, causing wet ceilings and walls. That was fixed, but when a new drain line (PVC) was installed, it wasn't supported properly, so sagged. That caused water to collect in it, and the water froze when Winter arrived, cracking the pipe. So the next Spring another leak with even more wet ceilings, walls and insulation. Mold began growing inside the air handler, flex ducts, and the walls that had been wet. It cost well over $10,000 to get that torn out and clean up the mold, not including any replacement of damaged material.

It's much better to install the unit in a closet, and have the ductwork run up into the attic space.

Post# 892277 , Reply# 13   8/2/2016 at 18:15 (327 days old) by wayupnorth (On a lake between Bangor and Bar Harbor)        

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I have oil baseboard hot water heat here and no matter how cold it is outside, and it does get mighty cold here, it is comfy inside. I just have an old Frigidare a/c in the bedroom window and I sleep fine. Ceiling fans in the rest of the house when it gets hot. If I want meat locker temperatures, I got it in my bedroom.

Post# 892673 , Reply# 14   8/5/2016 at 20:02 (324 days old) by warmsecondrinse (Fort Lee, NJ)        

A few thoughts/questions:


1. How would you manage humidity in the summer? Is that not an issue where you are?


2. Do night time temps in the summer consistently drop low enough and stay there long enough to remove the heat accumulated during the day? The less of an average temperature differential, the more radiators (and accompanying fans) would be needed. 


3. Do you plan to insulate and heat the basement? That's a factor in design as well.


4. There is the cost and payback time vs. conventional heating/cooling systems. Included in the cost of the system would be the wages you would have earned had you been earning income instead of installing your system.


5. You mentioned a duct system partially installed. Where does it lead to and form at present?



Post# 914868 , Reply# 15   1/9/2017 at 23:48 by jkbff (Gladstone, ND)        

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So... I thought I'd update this post, because I keep going back and forth on ... everything.

I have a gas fireplace and a gas cooktop. All of the heat is electric baseboard heat..

I just got my december bill.. ......

I keep 3 rooms below 60, the garage at 45, had a new insulated door installed, keep the fireplace set at 68, the bedroom set at 65 and two space heaters set at 60, one in the main level bath, one in the master bath....

My bill was 260 bucks. 70 for gas, the rest electricity...

The hot water heater is electric.. ... and its in the garage......

Sorry for the lines, I am very frustrated...

Anyways. Found out, after a few days of -33 temps, that the windows aren't insulated.. They were installed by a southern contractor.. So now I need to cut the sheetrock returns out, insulate the windows and then probably make casings for them... The doors aren't installed properly, I've replaced the seals on the ones that leak the most but the frames aren't insulated... Same southern contractor...

The custom tiled showers all leak.. The builder didn't pay the tile guy, he quit, the flooring guy installed the shower tile.. Didn't use a waterproof membrane. ... The sheetrock in the garage needs to come down because of the leaks, so when that happens, I'll have the ceiling spray foamed.

The garage foundation walls are roughly a foot thick cement.. 9' tall. It holds temp well, except for the windows. The 2" thick garage door is doing pretty good. -33 out, 45 in the garage, the heater not even running constantly.

As far as the AC.. I like the idea putting an air handler / AC a-coil upstairs, in a closet or something. I could use the middle room closet, have the return cut into the hall wall and the ceiling directly below... I wish I could find an easy site to help plan HVAC layout, but everything I find has a charge... Originally I've been thinking of the most effective way to have the unit downstairs, but that doesn't seem feasible.

With all the stuff I have ahead of me, I do want to do a gas based hot water heat system (with a blower) to each room. I want it zoned. That seems like it would be the most efficient vs cost effective... I mean I get that electric heat is 100%, but it isn't cheap. (Is there a way to tie hot water heat in with the house's hot water supply?)

Don't mind my rambling... I.. have so much going on in my head with all this crap.

I have looked at possibilities of mini-splits, multi unit mini-splits, ptacs, wall units and other stuff.... I would love a Lennox SLP98V Variable-capacity gas furnace with a matching AC unit.. I would love to have something that can run low when maintaining and balls to the wall when needed. I need to find something that I can order at cost... I was quoted 12k to install a unit. ... :/

Post# 914879 , Reply# 16   1/10/2017 at 02:30 by jkbff (Gladstone, ND)        

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I did find that. Maybe the middle floor would be best for an air handler/ac coil.

Post# 914885 , Reply# 17   1/10/2017 at 03:48 by foraloysius (Groningen, the Netherlands)        

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Hydronic heat with radiators is a relatively cheap system to run. Some boilers are very efficient, I have one that has an efficiency of over 100% due to the warmth of the condensation being regained. I find that radiators give a more comfortable feel than heating with forced air. With such a system you can't cool though, but it's good in combination with a multi split unit. These have a heat pump so you can use it for local heating in spring and autumn too.

Post# 914971 , Reply# 18   1/10/2017 at 14:06 by firedome (Binghamton NY & Lake Champlain VT)        
We installed a new split unit...

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cold climate Mitsubishi heat pump with their new technology that's designed to work near 100% to below -15-20 range in our Northern Vermont place. It gets pretty cold there as well, only 40 miles from Canada. So far very impressed with it's performance and efficiency. Of course it's A/C in the summer as well. By next winter it will be powered by this:

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