HVAC/Efficiency Guys

[Gimmered]

My AC A-coil was freezing up the other day. All the kids were back and we were working it pretty hard with a full house and some cooking going on. Got the AC guy at the house the next day. We had already melted the ice off and had it cooling some but the was a bit low on Freon. Took 3 pounds, and it hadn't been topped off for 5 or 6 years, not a huge leak. 15 year old system.

When I had it put in 15 years ago I went with most efficient I could afford at the time. 16 seer heat pump with a 95% efficient gas back up. I figure I've got 3 to 5 years left in it. As any good HVAC guy would he was trying to sell me a new system. We were talking over options and one thing he brough up was a hydronic air handler to replace my gas furnace. Got me doing some research.

I'm a big Rinnai fan. Quality products. I see they have an air handler designed to run with their tankless water heaters, or tankless boilers. I just installed a new tankless last winter. The spec would actually work with this air handler, but I would be more inclined to go with a combi boiler just a bit larger.

My real question is, I'm seeing some impressive numbers out there comparing hydronic to natural gas furnace. Water is more efficient to heat than air. The numbers I'm seeing is 30% more efficient. So, @Joes Place or any other would you like to take a stab at this? My water heater is 86%, while my gas furnace is 95%. I wouldn't buy a boiler that was less that 96%. With the federal tax break of $600 it would be silly. One thing I do know is the tankless is fully modulating. water heater or boiler it runs through a loop so after it loops back, you're dealing with warmer water so less flame.

 

[Firekirknow]

Ah can you like shut up man.

 

[Joes Place]

My AC A-coil was freezing up the other day. All the kids were back and we were working it pretty hard with a full house and some cooking going on. Got the AC guy at the house the next day. We had already melted the ice off and had it cooling some but the was a bit low on Freon. Took 3 pounds, and it hadn't been topped off for 5 or 6 years, not a huge leak. 15 year old system.

When I had it put in 15 years ago I went with most efficient I could afford at the time. 16 seer heat pump with a 95% efficient gas back up. I figure I've got 3 to 5 years left in it. As any good HVAC guy would he was trying to sell me a new system. We were talking over options and one thing he brough up was a hydronic air handler to replace my gas furnace. Got me doing some research.

I'm a big Rinnai fan. Quality products. I see they have an air handler designed to run with their tankless water heaters, or tankless boilers. I just installed a new tankless last winter. The spec would actually work with this air handler, but I would be more inclined to go with a combi boiler just a bit larger.

My real question is, I'm seeing some impressive numbers out there comparing hydronic to natural gas furnace. Water is more efficient to heat than air. The numbers I'm seeing is 30% more efficient. So, @Joes Place or any other would you like to take a stab at this? My water heater is 86%, while my gas furnace is 95%. I wouldn't buy a boiler that was less that 96%. With the federal tax break of $600 it would be silly. One thing I do know is the tankless is fully modulating. water heater or boiler it runs through a loop so after it loops back, you're dealing with warmer water so less flame.

Just out of the gate, the SEER ratings on the air handler don't appear all that great when combined w/ the AC systems they list as compatible.

So, if I were going to look at one of these, I would not combine w/ my AC. I'll have to dig into these - have not seen this before, and I'll be due for a new water heater in a few years, although my furnace still has 10 yrs of life on it.

 

[Joes Place]

Only see models that go up to 60,000 BTU heating; I think my system runs 80,000 (if I recall correctly here). So, what I'm seeing there would not work w/o an additional unit.

 

[Gimmered]

Just out of the gate, the SEER ratings on the air handler don't appear all that great when combined w/ the AC systems they list as compatible.

So, if I were going to look at one of these, I would not combine w/ my AC. I'll have to dig into these - have not seen this before, and I'll be due for a new water heater in a few years, although my furnace still has 10 yrs of life on it.

There is a 3 ton Trane that they show as 15 seer, that's listed as 16. I could live with that. My HP is a 4 ton, but it was sized for heat not cooling. I never use the HP any more, too many condensers were dying prematurely and my gas is on a 12 month budget locked in for 2 years normally.

 

[Gimmered]

Only see models that go up to 60,000 BTU heating; I think my system runs 80,000 (if I recall correctly here). So, what I'm seeing there would not work w/o an additional unit.

That is based on 140 degree water. With a boiler that could be bumped up to 70,000+ at 160 degrees. Mine is a 70,000 input @95% so 66,500. My thoughts were I could leave it at 140 and if it struggled in the dead of winter I could bump it up. My furnace now could sweat you out at 20 below.
My goal has been to move to smaller units as improvements to the equipment and the house have been made.

 

[Joes Place]

That is based on 140 degree water. With a boiler that could be bumped up to 70,000+ at 160 degrees. Mine is a 70,000 input @95% so 66,500. My thoughts were I could leave it at 140 and if it struggled in the dead of winter I could bump it up. My furnace now could sweat you out at 20 below.
My goal has been to move to smaller units as improvements to the equipment and the house have been made.

If you have any insulation to upgrade or higher R windows, you'd also likely get by w/ lower BTU output (compared to how the unit was sized if with lower grade insulation).

If I were 'on the edge', I'd probably get an assessment performed to identify actual BTU needs, to be certain.

 

[Gimmered]

If you have any insulation to upgrade or higher R windows, you'd also likely get by w/ lower BTU output (compared to how the unit was sized if with lower grade insulation).

If I were 'on the edge', I'd probably get an assessment performed to identify actual BTU needs, to be certain.

It's really hard to get an actual assessment. Even the guy that was working on mine said he wouldn't want to go smaller. Part of my issue now is, with the 4 ton unit, I need to leave my basement vents open at least part way in the summer. It can be really cold down there. dropping to a 3 ton I could just cool the main floor and make the whole house more comfortable.

If you do decide to replace your water heater, these newer Rinnai kick ass and have the $600 federal tax credit. I effed up and bought a model that would bolt right up to the wall where my old one was. Had I know about the tax credit I could have had a much better model for less out of pocket. Mine qualified for a $300 rebate from my gas provider, Black Hills Energy, but not for the $600 federal. I would have had a $1400 unit for just over $500.

 

[Gimmered]

If you have any insulation to upgrade or higher R windows, you'd also likely get by w/ lower BTU output (compared to how the unit was sized if with lower grade insulation).

If I were 'on the edge', I'd probably get an assessment performed to identify actual BTU needs, to be certain.

Got the turn key package with the 4 ton unit, 90,000 BTU combi Boiler and air handler in my cart from https://www.supplyhouse.com for $8445. 16 seer that's listed as a 14.5 by Rinnai.

 

[Joes Place]

Got the turn key package with the 4 ton unit, 90,000 BTU combi Boiler and air handler in my cart from https://www.supplyhouse.com for $8445. 16 seer that's listed as a 14.5 by Rinnai.

Can you link the actual models? Curious on this, as even though I won't need for a while here, would like to document for future replacements/upgrades.

SEER is a little lower than I'd prefer, but I expect as tech evolves it might improve by the time I'm poking around for updated HVAC here. Nice info!

 

[Uniformed_ReRe]

Before buying a new AC in the middle of the summer, make sure the drain lines are flushed and clear, and the outdoor heat pump unit is not clogged with grass clippings. I assume you've already changed/cleaned the air filter, but that too.

In my experience, those are common causes of evaporator coils freezing and short cycling.

I'm no HVAC tech, but I am a Floridian.

 

[Joes Place]

Before buying a new AC in the middle of the summer, make sure the drain lines are flushed and clear, and the outdoor heat pump unit is not clogged with grass clippings. I assume you've already changed/cleaned the air filter, but that too.

In my experience, those are common causes of evaporator coils freezing and short cycling.

I'm no HVAC tech, but I am a Floridian.

Drain line is a major issue here in CO, where the trap will dry out over wintertime and dust can accumulate in the trap, then creating a mud-block in the line.

Make sure you have access to the trap/drain area, pour some water into it every month or so during the dry months AC is not used, and get a small snake brush to clear it out every spring and you'll prevent major problems with water backing up and getting into your system's electronics.

I always test mine by pouring a half cup or more of water thru and making sure it comes out the drain end; my installer did not include a cap for drain/trap access, so I had to drill and tap the PVC to make one, myself. Would have cost me $200-400 to have another HVAC guy re-pipe the whole drain outlet to add one. It looks a little ghetto, but it works fine

 

[Gimmered]

Can you link the actual models? Curious on this, as even though I won't need for a while here, would like to document for future replacements/upgrades.

SEER is a little lower than I'd prefer, but I expect as tech evolves it might improve by the time I'm poking around for updated HVAC here. Nice info!

Comfort-Aire RSG1648S1M and matching 4 ton coil.

Air Handler Rinnai AH166CP. I need to find out if I want or need the circulation pump with a boiler. I would with a tankless water heater.

Boiler i090CN 90,000 BU combi boiler.

I'm starting to rethink the idea a bit and am looking into twinning 2 separate 40.000 BTU air handlers into the same ductwork and adding zoning wall plate grills. I could run one or the other or both. Not the perfect solution, but i's better than ripping out my ductwork. I could get by with one 199,000 BTU tankless, a 1.5 ton AC for the lower level and a 2.5 ton AC for the Main floor. The tankless would cost about $500 after rebates.

I did see a site that shows seer savings over time. A 3 ton 16 seer AC would only save about $800 in a 15 year period over a 14 seer. Not as much as I would have expected.

SEER Energy Savings Calculator for Air Conditioners

Use our free SEER Energy Savings Calculator to instantly see how much energy you save by upgrading to an air conditioner with a higher SEER / SEER2 rating.

www.seerenergysavings.com

 

[Joes Place]

I did see a site that shows seer savings over time. A 3 ton 16 seer AC would only save about $800 in a 15 year period over a 14 seer. Not as much as I would have expected.

SEER Energy Savings Calculator for Air Conditioners

Use our free SEER Energy Savings Calculator to instantly see how much energy you save by upgrading to an air conditioner with a higher SEER / SEER2 rating.

www.seerenergysavings.com

This is why when I upgraded my HVAC years ago, I did some of my own research on AC units; Had something around 13.5/14 SEER and my initial quote was for a mid-range 17 SEER model.

I'd found a newer midrange model that had a 5-stage system and 19/20 SEER, that turned out to be pretty much the same price. Much larger savings difference when you get to the 20-23 SEER stuff, depending on what you start out with. My outside AC unit is quieter, just around the corner from my back deck, than my neighbor's unit that's all the way around the other side of my house. Lowered my cooling bills substantially, quieter and much stabler house temps with that unit along with the high-efficiency DC blower that uses 50-60W compared to the old A/C blower that used over a half-kilowatt to run.

So, if you understand a little about this stuff, it is worth doing some online footwork, as you may find/identify options your installer was unaware of, that he can quote and get for you.

 

[TailgateTom]

Were your Coils washed clean and new filters put in?

 

[Gimmered]

es,

Were your Coils washed clean and new filters put in?

Yes, the system was fine other than being low on freon. I had to have freon added after about 9 or 10 years of use and again this week, 5 or 6 years later. It's fine unless the leak get worse, then I'd need to figure out what I'm going to do.

I don't want to do anything until I can switch to R454b. I have no desire to be paying for R410a in 12 years or so.

 

[Joes Place]

es,

Yes, the system was fine other than being low on freon. I had to have freon added after about 9 or 10 years of use and again this week, 5 or 6 years later. It's fine unless the leak get worse, then I'd need to figure out what I'm going to do.

I don't want to do anything until I can switch to R454b. I have no desire to be paying for R410a in 12 years or so.

454b.....455b........whatever it takes...

 

[SansAgain]

My AC A-coil was freezing up the other day. All the kids were back and we were working it pretty hard with a full house and some cooking going on. Got the AC guy at the house the next day. We had already melted the ice off and had it cooling some but the was a bit low on Freon. Took 3 pounds, and it hadn't been topped off for 5 or 6 years, not a huge leak. 15 year old system.

When I had it put in 15 years ago I went with most efficient I could afford at the time. 16 seer heat pump with a 95% efficient gas back up. I figure I've got 3 to 5 years left in it. As any good HVAC guy would he was trying to sell me a new system. We were talking over options and one thing he brough up was a hydronic air handler to replace my gas furnace. Got me doing some research.

I'm a big Rinnai fan. Quality products. I see they have an air handler designed to run with their tankless water heaters, or tankless boilers. I just installed a new tankless last winter. The spec would actually work with this air handler, but I would be more inclined to go with a combi boiler just a bit larger.

My real question is, I'm seeing some impressive numbers out there comparing hydronic to natural gas furnace. Water is more efficient to heat than air. The numbers I'm seeing is 30% more efficient. So, @Joes Place or any other would you like to take a stab at this? My water heater is 86%, while my gas furnace is 95%. I wouldn't buy a boiler that was less that 96%. With the federal tax break of $600 it would be silly. One thing I do know is the tankless is fully modulating. water heater or boiler it runs through a loop so after it loops back, you're dealing with warmer water so less flame.

I have a masters license in plumbing and hydronics and my advice would be to go with hydronic heating system. The radiant heat so much more comfortable and consistent and you don’t have scorched air in the winter. You can run pex through the first floor between the joists so you have underfloor heating and up to fin tubes or radiators on upper floors.

 

[Gimmered]

I have a masters license in plumbing and hydronics and my advice would be to go with hydronic heating system. The radiant heat so much more comfortable and consistent and you don’t have scorched air in the winter. You can run pex through the first floor between the joists so you have underfloor heating and up to fin tubes or radiators on upper floors.

That will be the plan, but it won't be radiant, it will still be forced air. I'm looking at all the options short of tearing out my trunk line and starting over. Even a zoned system would likely mean knocking hole in the walls. It wouldn't take any time at all to spend more money than I would ever save. The ROI just isn't there.
Fortunately I have some time to explore the options.

 

[SansAgain]

That will be the plan, but it won't be radiant, it will still be forced air. I'm looking at all the options short of tearing out my trunk line and starting over. Even a zoned system would likely mean knocking hole in the walls. It wouldn't take any time at all to spend more money than I would ever save. The ROI just isn't there.
Fortunately I have some time to explore the options.

Heat pump and call it a day. You’re overthinking.

 

[Gimmered]

Heat pump and call it a day. You’re overthinking.

I have a heat pump and am very familiar with all the pros and cons. Mine will handle heating the house to 75 degrees down to 8 degrees. It is very likely though if I kept using the heat pump all these winters, I'd had to replace everything a long time ago. Also I have no desire to walk by registers blowing 90 degree air.

 

[Joes Place]

Fortunately I have some time to explore the options.

This is what most people don't do.

They push major investments in their house like this off, until what they have breaks and they're in a rush.
And sound decisions are rarely made in a panic/hurry.

 

[Joes Place]

I have a heat pump and am very familiar with all the pros and cons. Mine will handle heating the house to 75 degrees down to 8 degrees. It is very likely though if I kept using the heat pump all these winters, I'd had to replace everything a long time ago. Also I have no desire to walk by registers blowing 90 degree air.

How old is the heat pump?

My parents had one for a 3-season porch that was an older Fujitsu, which struggled below 10°F.
New Mitsu model is rated 15 or so degrees lower, and worked down to 0°F this past winter. Didn't really get "tested" much below that, but the designs/tech on those keep getting better for cold weather performance.

 

[Gimmered]

How old is the heat pump?

My parents had one for a 3-season porch that was an older Fujitsu, which struggled below 10°F.
New Mitsu model is rated 15 or so degrees lower, and worked down to 0°F this past winter. Didn't really get "tested" much below that, but the designs/tech on those keep getting better for cold weather performance.

It's a 15 year old Gibson (Nordyne). My HVAC guy was a retied auto mechanic that did HVAC till his late 70's, when he broke his neck working. He loved all the newest technology and tools. He had me try a different thermostat that would sense when the HP couldn't keep up, and forgot to install a thermo-cutoff switch. He wanted to come install the switch but I wanted to see how well it would do.
There is no cold start kit on this, they really weren't a thing yet. And it's oversized for heat. I can't complain at all with what I have, I'm just looking for a efficient way to balance the 2 levels better. My house was built to be a 2 level duplex and has a garden level basement. When I replaced the duct work I made it harder to balance the temperature between the 2 levels. In 1950 when it was built, the plan was to use brute force. I would have 3 months out of the year where I would use 400 therms a month before I replaced the units.

 

[tadopkok]

One tip I came across recently is sealing up any leaks in your ducts. Apparently, a lot of energy is lost through these gaps, so it’s worth getting them checked out. And don't forget to change your filters regularly – it’s a simple thing, but it keeps the system running smoothly.

 

[CLUB215]

Years ago I did some calcs on a larger commercial building looking to replace their boiler. We recommended they choose the less efficient single stage model over the three stage and use the savings in cost to replace their windows and add insulation in the attic.

 

[Joes Place]

Years ago I did some calcs on a larger commercial building looking to replace their boiler. We recommended they choose the less efficient single stage model over the three stage and use the savings in cost to replace their windows and add insulation in the attic.

True-

Higher efficiency stuff doesn't help all that much, when you have really crapping windows and insulation
I've replaced all my contractor-grade single-pane windows here - lots of homes in my neighborhood still have their original contractor windows, which are absolute junk.

 

[CLUB215]

True-

Higher efficiency stuff doesn't help all that much, when you have really crapping windows and insulation
I've replaced all my contractor-grade single-pane windows here - lots of homes in my neighborhood still have their original contractor windows, which are absolute junk.

It's all about the rate of return for your investment. The 3 stage boiler was going to cost over $40k more in equipment and plumbing and would have taken years to pay for itself. We were able to show that spending $40k upgrading the windows and insulation paid for itself in shorter time than the higher efficiency boiler would have.

 

[Joes Place]

It's all about the rate of return for your investment. The 3 stage boiler was going to cost over $40k more in equipment and plumbing and would have taken years to pay for itself. We were able to show that spending $40k upgrading the windows and insulation paid for itself in shorter time than the higher efficiency boiler would have.

Running the numbers is always the best strategy.... people get too caught up in marketing and 'efficiency' #s
I ran the numbers on my HVAC options when upgrading, and higher efficiency furnace and higher SEER paid off in <5 yrs for me.
Had already done half my windows and just finished the rest last year. Aside from $$ savings, I noticed substantially better 'comfort' around the house - have one wall that connects to above-garage attic that is poorly insulated that I need to get some 1" sheet foam insulation and put that up along those walls in that garage attic/storage area. Just a pain to move stuff I have stored up there to do it, but will likely be my fall project this year.