Building a custom home - HVAC options - could use a bit of help please!

[orezok]

We are in the process of upgrading our 17 year old 80% propane furnace and 5 ton split unit to mini splits. About 18 months ago I upgraded the master BR and bath to minis. It allows us to have the temp we want at night while sleeping without heating or cooling the whole house. We absolutely loved it so much that now I am converting the whole house to mini splits.

The units are almost silent the air handler fan runs at a low speed constantly so the air keeps circulation and the hot air does not concentrate at the ceiling. The temps are very consistent throughout the room.

Since the compressors are inverters they constantly vary the load saving a lot of power. The original 18K with two 9K splits unit only draws 4 amps 240v on my clamp on meter when fully on.

The best part is that the SEER is 22!

There are a few downsides. First each air handler has it’s own thermostat, but that can be handled by using a phone app to control each unit as they are internet connected. It’s nice to come home to a warm house when gone for the day.

The second this is that because we are in the desert, we have a whole house humidifier for use in the winter heating season. We have been using a small humidifier in the BR and will probably have to get a large unit for the great room.

 

[jk96]

We are in the process of upgrading our 17 year old 80% propane furnace and 5 ton split unit to mini splits. About 18 months ago I upgraded the master BR and bath to minis. It allows us to have the temp we want at night while sleeping without heating or cooling the whole house. We absolutely loved it so much that now I am converting the whole house to mini splits.

The units are almost silent the air handler fan runs at a low speed constantly so the air keeps circulation and the hot air does not concentrate at the ceiling. The temps are very consistent throughout the room.

Since the compressors are inverters they constantly vary the load saving a lot of power. The original 18K with two 9K splits unit only draws 4 amps 240v on my clamp on meter when fully on.

The best part is that the SEER is 22!

There are a few downsides. First each air handler has it’s own thermostat, but that can be handled by using a phone app to control each unit as they are internet connected. It’s nice to come home to a warm house when gone for the day.

The second this is that because we are in the desert, we have a whole house humidifier for use in the winter heating season. We have been using a small humidifier in the BR and will probably have to get a large unit for the great room.

We have a similar setup only with geo and zoned duct. 6 separate zones with whole house humidifier tied in.. Master is alone on one of those zones. Having the zone controls is really nice.

 

[newbury]

<snip> the HVAC company is ready to start working now. Any help, advice or guidance offered would be most appreciated.

Thanks!

If he's ready to start working NOW it's a little late BUT
Look into mini-splits.
Unless you already have the ductwork planned for and installed it's a much easier installation.

 

[MasseyFerg231]

Hi!

We are in the process of building a 3200 square foot custom home in North Carolina. We have been approached by the HVAC contractor and given three options for the systems we can choose (he has estimated a 2.5 ton system upstairs and a 3.5 ton system downstairs). They are all Trane systems and are:

Option #1: The XB1000 air conditioner (10 SEER) with the XE80 gas furnace for approximately $12,000***OR***
Option #2: The XR12 air conditioner (up to 13 SEER) with the XR90 gas furnance for approximately $15,000***OR***
Option #3: The XL14i air conditioner (up to 15 SEER)with the SV90 gas furnance for approximately $18,800.

Our questions are:

1. In light of the upcoming regulation changes, what would be the mininum expected requirement for a custom home?

2. What are the real differences in comfort one might feel in the different systems (I am more sensitive to heat and humidity versus cold)?

3. We are not on a gas line, therefore, we will be on propane and option #3 includes a two-stage gas furnance. What kind of savings can we expect to see with a two-stage system?

4. We have a fairly open floor plan; however, there were no deisgned-in locations for the return ducts. Our contractor has proposed two locations within 7 feet of each other (no barrier walls involved) for the first floor. Will this be sufficient to adequately draw air?

5. He has also presented the option of an electronic air cleaner at a cost of $1495 - are these worth that expense? Do they really help with dust?

Our general contractor has not offered the option of getting other "bids" to verify fair pricing and the HVAC company is ready to start working now. Any help, advice or guidance offered would be most appreciated.

Thanks!

Google Green Building Advisor. There is a wealth of information related to HVAC systems.
Your hvac contractor should be performing a manual J calculation to size your system. If not, you should find someone that will.

As for returns, I would not build a new house without ducted returns in all bedrooms. If it’s too late, you can at least install a jumper duct from inside the bedroom to the hallway to help with flow.
I just had upstairs unit replaced this summer with the XL14i. So far now issues.

check utility providers as they may offer rebates with certain efficiencies of units. It won’t be enough to pay for upgrades but it might get you a couple hundred back.
If your ducts are ran in un-conditioned spaces, make sure they are sealed and insulated.

 

[MasseyFerg231]

I've built 8 new houses in my life. I've always used "the best" option for HVAC. Never go on the cheap.

Based on the options your builder has given you, I'd seek out another quote on your own from another HVAC contractor. Carrier or Trane are both good systems. 15 seer is lower than I would go. They make equipment up to 20 seer now. Higher the seer the more efficient it is. I have 17 seer. Very efficient and low utility bills. And with you being on propane, the more efficient the better.

Also, you should be able to get a "zoned" system. One AC condensor, one furnace with 2 zones of ductwork. It's what I have in my home now. Works great. Separate thermostats for each zone. Costs a little more for ductwork installation, but lowers the overall costs on 2 condensors and furnaces.

And putting both return ducts 7' apart is mal-practice IMO. I'd never put them that close together. Contractor is trying to make it easy on himself (jeeze...there's a surprise).

And remind your builder whose house it is, and who is paying the bills. If you're not satisfied with his HVAC contractor he can easily find another for you. He just doesn't want to.

If you go the zoning route, do so with a hvac co tractor that is knowledgeable about these systems. Otherwise may not go well.

 

[3Ts]

All these are good suggestions. The SEER you were quoted is way to low! Your monthly energy bills will be high. I have a 18 SEER 4 ton unit with spray foam insulation in 2200 sq ft. house. Insulation and sealing against air infiltration is very important and will have a big impact on your energy bills and what size of HVAC you'll need.

Fine Homebuilding was mentioned - that's an excellent source, but if you can't get ahold of the magazine, one of the frequent contributors is Matt Risinger who builds high end homes in the Austin area. He has videos on youtube, check them out.

Risinger on HVAC

Manual J calculations were mentioned. They are required by code. Where I am, inspections are not required and the HVAC contractors can not do a manual J calculation. They know generally what it is, but don't have the software to it, nor do they have the knowledge of what needs to go into a manual J calculation. There are also calculations for duct size which I think is a manual D calculation. So, I'd push for the manual J and D calculations, but you may not get anything or if you do it may be meaningless depending on where you are.

 

[truckdiagnostics]

In the newer tighter homes it is the indoor moisture you need to worry about. Everybody talks about sealing the home but how are you going to get the air exchanges. If you have bath fans, range hood where is make up are coming from? Basically you build a tight home then you have to poke a hole in it. How this is done also depends on where you live. Depending on where you live you want to run positive and negative pressure in your home at different times of year. In summer if you ac is not sized right so that it runs long enough to drop the humidity you can get it cold but it will not feel cold because the humidity is high. Where your at I would be looking at EVR and a whole house dehumidifier. And to get that more right they should be ducted when the house is new. You can use the whole house dehumidifier to dehumidify the make up air when coming into the home.

Model 8192 Ventilation System with Dehumidification

The AprilAire Model 8192 ventilator with dehumidification brings fresh air from outdoors into the home, while removing moisture. Contact a Pro today.

www.aprilaire.com

this as a lot of good information

 

[mikester]

I wouldn't hesitate to go with cold climate mini-split heat pumps again. I've had mine for for 5years now and they work well down to -30oC.

Spend more money on better insulation, thermal breaks, air sealing, HRV, and most energy efficient doors and windows.

Remember that 80% of the building's cost during its lifetime is in the day to day operation, not the construction.

 

[milkman636]

Hi!

We are in the process of building a 3200 square foot custom home in North Carolina. We have been approached by the HVAC contractor and given three options for the systems we can choose (he has estimated a 2.5 ton system upstairs and a 3.5 ton system downstairs). They are all Trane systems and are:

Option #1: The XB1000 air conditioner (10 SEER) with the XE80 gas furnace for approximately $12,000***OR***
Option #2: The XR12 air conditioner (up to 13 SEER) with the XR90 gas furnance for approximately $15,000***OR***
Option #3: The XL14i air conditioner (up to 15 SEER)with the SV90 gas furnance for approximately $18,800.

Our questions are:

1. In light of the upcoming regulation changes, what would be the mininum expected requirement for a custom home?

2. What are the real differences in comfort one might feel in the different systems (I am more sensitive to heat and humidity versus cold)?

3. We are not on a gas line, therefore, we will be on propane and option #3 includes a two-stage gas furnance. What kind of savings can we expect to see with a two-stage system?

4. We have a fairly open floor plan; however, there were no deisgned-in locations for the return ducts. Our contractor has proposed two locations within 7 feet of each other (no barrier walls involved) for the first floor. Will this be sufficient to adequately draw air?

5. He has also presented the option of an electronic air cleaner at a cost of $1495 - are these worth that expense? Do they really help with dust?

Our general contractor has not offered the option of getting other "bids" to verify fair pricing and the HVAC company is ready to start working now. Any help, advice or guidance offered would be most appreciated.

Thanks!

Trane makes as good of equipment as anybody. I'd definitely recommend going with option #3 of the ones presented. Having separate units for upstairs and down does provide a basic level of "zoning", which is beneficial. Central systems can also provide much better air filtering than the mini-splits. I'd recommend exploring the air filters the builders are proposing as well. A big benefit of two stage or modulating units is the longer circulating fan cycle times in low stage operation, the house will feel more evenly heated/cooled, and have better humidity and dust control.

 

[Rustyiron]

The tradesman gets stuck in their own rut.
Find a contractor that's familiar with ductless mini splits. They are fantastic and those tin beaters guys in the rut will discourage you simply because it's out of their comfort zone of what they know. What they don't know is it's still the basic "thing" that they're doing every day without the tin.
Very comfortable
Very efficient and arguably a simpler and faster installation.
Don't confuse these with the pretty lousy ducted "heat pump" of the 80's & 90's, not even close.