I generally stay out of the home HVAC threads because, well, most people want to know what the cheapest solution is.
I saw in the latest thread someone asking about mini-splits. There's several versions/product lines of "mini-splits".
First off, I have been a fan of the newer technology of "mini-splits" for over 10 years. In a former life I worked as an HVAC designer at a few engineering firms (MEP) doing commercial and industrial HVAC, Piping and Plumbing design for over 20 years. I am proficient in cheap residential crap (5 tons and below), packaged DX, chilled water, VAV/PIU, water source heat pumps, with a minor in industrial cooling water, steam, process, plumbing. I have also minored in mechanical contracting doing piping, structural and some HVAC. I can fake my way around a construction site until someone smarter comes along.
Anyway, I skipped on the chance to put my money where my mouth (and brain) was in 2015 when we bought a house and it needed both HVAC systems replaced. I hem-hawed at the idea of installing a Daikin 5-ton Multi-port condensing unit (VRV-S Commercial System) with two indoor 'convertible' fan coil units, connecting to the existing ductwork. More or less a typical system change-out except the equipment was going to be state of the art like no other house had.
These "mini-splits" that are multi-port condensing heat pump units can supply refrigerant to 2, 3, maybe 4 indoor units and do so with NASA-grade precision, making your home/office/etc. more comfortable than you could ever imagine while reducing your power bill to make you think you've installed solar panels. It's also quiet as a cotton ball and will last longer than your typical residential junk. They are also capable of providing heat to one area and cooling to another, but the costs climb even further than what a system is that can only heat or cool at one time.
There are residential lines of multi-port systems, but most manufacturers stop those at 3 tons. You can also opt for single-port systems, where you have one condensing unit outside for one indoor unit. Most manufacturers worth looking at make indoor units that look and act just like the indoor unit you have now.
Another advantage is there is usually no need for strip heat with these systems.
Recently I had a Daikin VRV-S system installed in my mother's house. After hours of thought and pondering, it was the only solution that made sense based on the requirements and existing infrastructure. She is 77 years old and suffers from some ailment where she is very cold all the time. She needs her house at 75 degrees or so (we've actually come down from 77-78 when she had a gas-fired furnace). She has a ~2500 sf house, all electric, with a 200-amp service. There was an existing 3-ton split system heat pump there, 15 years old (original to the house) with a zone damper system to throw some air to the upstairs when called for. They don't use the upstairs, can't climb stairs (it's a teenager suite). So I was faced with no gas, no additional electrical capacity for increased strip heat, I wanted to get rid of the zone damper crap and I needed to make darn sure the new system could supply hot air and heat the house to her demands....through the existing ductwork. Oh yeah, she had been using 1500w heaters to keep warm, December and January power bills were $415.
So I spec'd out the 4-ton Daikin VRV-S Condensing unit, a 3-ton indoor unit and 1.5-ton indoor unit. The 3-ton unit was to connect to the ductwork serving downstairs main house and the 1.5-ton unit was to connect to the ductwork serving the upstairs. This eliminated the zone damper system. Both units can run independently but use the same condensing unit. The condensing unit also only runs as much as is needed for the demand, meaning it ramps up and down all day long. You might think this is counter-intuitive to energy savings and comfort, but after watching it and observing it for 2 weeks, it is beyond the understanding of many who have only experienced the typical bang-on, slam-off residential and commercial HVAC equipment.
What this system does is 'chase' the desired setpoint all day, meaning if it is set to 72 and in heating mode, your indoor temp condition is going to show 71 but it's going to be very comfortable and you will never know it's "1 degree from setpoint" because the system is probably running at 15% or so (both the indoor fan and condensing unit) and delivering a very small amount of conditioning all the time to maintain a perfect temperature in the house. There is no "heat it up, shut off and allow the temp to fall, repeat the cycle". Comfort is unreal.
No, this was not "cheap", it wasn't even in the same ballpark compared to pricing a like-for-like system change out with typical low-efficiency residential equipment. But I am 110% satisfied and kick myself nearly everyday for not doing this at my house 5-1/2 years ago. I had this priced by 4 contractors - all commercial contractors and 3 of them were in the same ballpark price-wise. The most expensive was a friend of mine who I knew was going to be high because he runs a tight ship but I had confidence in the others or I wouldn't have called them in the first place. Before I get into the pricing- here's the scope:
1. Demolish the existing condensing unit and indoor air handling unit
2. Install new 6-space subpanel in attic, use existing 60a circuit to power this and power two new indoor air handling units with this
3. Intercept existing 40a circuit in attic, use junction box to splice in new cable to run to new condensing unit location
4. Provide Daikin 4-ton VRV-S condensing unit, refrigerant piping, y-branch splitters, dryers and other refrigerant piping accessories
5. Provide Daikin 3-ton and 1.5-ton indoor convertible air handling units, new unit stands, return and supply plenums, new additional ductwork needed to connect to existing, new power wiring, new Daikin wifi thermostats, thermostat wiring, line-hide or metal covering over new refrigerant piping up exterior wall to attic.
Daikin also wanted to include factory start-up ($$$) because they wanted to make sure everything was right.
Total cost was about $17,000. Just for reference, I had one contractor beg me to allow him to offer an alternative. That was a 16 or 18 SEER Bryant 3-ton split system heat pump for down stairs and a Daikin 1.5 ton residential line mini-split for the upstairs (a high-wall indoor unit, not ducted), this was $12,800. This was almost a slap in the face, as I have no regard for Bryant equipment and there was NO part-load capacity with the 3-ton system. Basically typical residential stuff and certainly not worth anywhere close to $4000 savings in my mind.
Anyway, a long post, but I wanted to share the experience. I know most really don't want to spend anything on HVAC, the basic theory is it shouldn't cost much, but you really get what you pay for.
I'll follow up with the February power bill and we will see what the energy savings is. I expect it to be more than $200/mo.
I saw in the latest thread someone asking about mini-splits. There's several versions/product lines of "mini-splits".
First off, I have been a fan of the newer technology of "mini-splits" for over 10 years. In a former life I worked as an HVAC designer at a few engineering firms (MEP) doing commercial and industrial HVAC, Piping and Plumbing design for over 20 years. I am proficient in cheap residential crap (5 tons and below), packaged DX, chilled water, VAV/PIU, water source heat pumps, with a minor in industrial cooling water, steam, process, plumbing. I have also minored in mechanical contracting doing piping, structural and some HVAC. I can fake my way around a construction site until someone smarter comes along.
Anyway, I skipped on the chance to put my money where my mouth (and brain) was in 2015 when we bought a house and it needed both HVAC systems replaced. I hem-hawed at the idea of installing a Daikin 5-ton Multi-port condensing unit (VRV-S Commercial System) with two indoor 'convertible' fan coil units, connecting to the existing ductwork. More or less a typical system change-out except the equipment was going to be state of the art like no other house had.
These "mini-splits" that are multi-port condensing heat pump units can supply refrigerant to 2, 3, maybe 4 indoor units and do so with NASA-grade precision, making your home/office/etc. more comfortable than you could ever imagine while reducing your power bill to make you think you've installed solar panels. It's also quiet as a cotton ball and will last longer than your typical residential junk. They are also capable of providing heat to one area and cooling to another, but the costs climb even further than what a system is that can only heat or cool at one time.
There are residential lines of multi-port systems, but most manufacturers stop those at 3 tons. You can also opt for single-port systems, where you have one condensing unit outside for one indoor unit. Most manufacturers worth looking at make indoor units that look and act just like the indoor unit you have now.
Another advantage is there is usually no need for strip heat with these systems.
Recently I had a Daikin VRV-S system installed in my mother's house. After hours of thought and pondering, it was the only solution that made sense based on the requirements and existing infrastructure. She is 77 years old and suffers from some ailment where she is very cold all the time. She needs her house at 75 degrees or so (we've actually come down from 77-78 when she had a gas-fired furnace). She has a ~2500 sf house, all electric, with a 200-amp service. There was an existing 3-ton split system heat pump there, 15 years old (original to the house) with a zone damper system to throw some air to the upstairs when called for. They don't use the upstairs, can't climb stairs (it's a teenager suite). So I was faced with no gas, no additional electrical capacity for increased strip heat, I wanted to get rid of the zone damper crap and I needed to make darn sure the new system could supply hot air and heat the house to her demands....through the existing ductwork. Oh yeah, she had been using 1500w heaters to keep warm, December and January power bills were $415.
So I spec'd out the 4-ton Daikin VRV-S Condensing unit, a 3-ton indoor unit and 1.5-ton indoor unit. The 3-ton unit was to connect to the ductwork serving downstairs main house and the 1.5-ton unit was to connect to the ductwork serving the upstairs. This eliminated the zone damper system. Both units can run independently but use the same condensing unit. The condensing unit also only runs as much as is needed for the demand, meaning it ramps up and down all day long. You might think this is counter-intuitive to energy savings and comfort, but after watching it and observing it for 2 weeks, it is beyond the understanding of many who have only experienced the typical bang-on, slam-off residential and commercial HVAC equipment.
What this system does is 'chase' the desired setpoint all day, meaning if it is set to 72 and in heating mode, your indoor temp condition is going to show 71 but it's going to be very comfortable and you will never know it's "1 degree from setpoint" because the system is probably running at 15% or so (both the indoor fan and condensing unit) and delivering a very small amount of conditioning all the time to maintain a perfect temperature in the house. There is no "heat it up, shut off and allow the temp to fall, repeat the cycle". Comfort is unreal.
No, this was not "cheap", it wasn't even in the same ballpark compared to pricing a like-for-like system change out with typical low-efficiency residential equipment. But I am 110% satisfied and kick myself nearly everyday for not doing this at my house 5-1/2 years ago. I had this priced by 4 contractors - all commercial contractors and 3 of them were in the same ballpark price-wise. The most expensive was a friend of mine who I knew was going to be high because he runs a tight ship but I had confidence in the others or I wouldn't have called them in the first place. Before I get into the pricing- here's the scope:
1. Demolish the existing condensing unit and indoor air handling unit
2. Install new 6-space subpanel in attic, use existing 60a circuit to power this and power two new indoor air handling units with this
3. Intercept existing 40a circuit in attic, use junction box to splice in new cable to run to new condensing unit location
4. Provide Daikin 4-ton VRV-S condensing unit, refrigerant piping, y-branch splitters, dryers and other refrigerant piping accessories
5. Provide Daikin 3-ton and 1.5-ton indoor convertible air handling units, new unit stands, return and supply plenums, new additional ductwork needed to connect to existing, new power wiring, new Daikin wifi thermostats, thermostat wiring, line-hide or metal covering over new refrigerant piping up exterior wall to attic.
Daikin also wanted to include factory start-up ($$$) because they wanted to make sure everything was right.
Total cost was about $17,000. Just for reference, I had one contractor beg me to allow him to offer an alternative. That was a 16 or 18 SEER Bryant 3-ton split system heat pump for down stairs and a Daikin 1.5 ton residential line mini-split for the upstairs (a high-wall indoor unit, not ducted), this was $12,800. This was almost a slap in the face, as I have no regard for Bryant equipment and there was NO part-load capacity with the 3-ton system. Basically typical residential stuff and certainly not worth anywhere close to $4000 savings in my mind.
Anyway, a long post, but I wanted to share the experience. I know most really don't want to spend anything on HVAC, the basic theory is it shouldn't cost much, but you really get what you pay for.
I'll follow up with the February power bill and we will see what the energy savings is. I expect it to be more than $200/mo.