Opinions wanted: solar, geothermal, 14 SEER, 16 SEER???

I've posted before when we were trying to decide if we wanted to deal with an electric company and a $50k+ hookup, or go off-grid. We ended up getting a territory swap with another electric company and paying $12k total for the install (we stopped considering off-grid at that time). The help we received from this forum was extremely valuable though and I'm back for more advice!

We are looking at our HVAC now. We wanted geothermal but after drilling a hole found out it was going to cost considerable more than planned. So now I'm playing with options:
1 - 14 SEER unit with about $4k of solar panels.
2 - 16 SEER unit with about $2k of solar panels.
3 - Go ahead and spend the extra for Geothermal. We would get 30% tax incentive for total install cost, but it would still come out considerably more than the other two options.

Part of my reasoning for this is the 30% for solar install and also PV will help with ALL the appliances in the house where geo would only help with HVAC.

Any opinions from you guys? Experience? I live in Kansas, it get's hot in the summer and cold in the winter if that helps any. Also a long term living arrangement, we plan on living here for 30yrs or more (until they drag me to a home). Ultimate goal is a cheaper utility bill...

Thanks!
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    You can get air to air mini-split units that are upwards of 26 SEER.

    http://www.fujitsugeneral.com/wallmountedRLS2.htm

    I would be looking at one of those.

    Cold weather heating--We have some folks here that use MiniSplits even with snow on the ground. I am not sure how efficient they are when it gets really cold--But it may work well for you.

    Also saves running air through ducting in the ceiling/under floor--Significant heat loss can happen with ducting.

    One person here recently talked about the issues that you want a wall unit mounted high for cooling, but mounted low for heating--You may need a ceiling fan or similar to mix the air for better temperature control.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • unseenone
    unseenone Solar Expert Posts: 61
    We switched from an old Rheem unit to a 16 Seer system, and cut our electrical use by more than half. The higher you go, the more expensive, but I can't say enough about how nice it has been. We went with carrier for the house. I recommend you buy the best one you can afford.

    Here is a tidbit to keep in mind. The efficiency of these units when they sell them, air based on the Air Conditioning. If you carefully review the specifications for the heating system, they are not very efficient at all. Seeing as we had already bought it, I did not add insult to injury to see what I might have been able to get.
  • Catscratch
    Catscratch Solar Expert Posts: 30
    My wife had minisplits at here job and she didn't like them. The company ended up getting rid of them for some reason. Anyway, she has to like whatever we come up with! We do have ceiling fans in the plans so that will help. And all ductwork will be in the envelope.

    I hadn't thought of comparing heat and air stats. I figured they were lumped together.

    Anyone have insight to geothermal? What about the idea of adding PV panels to a cheaper system to lower bills?

    Thanks for the comments so far!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    I worry that the water pump draws a lot of power for the circulation loop.

    Have you gotten an estimate on the size of water pump you would need? 1hp or more?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Catscratch
    Catscratch Solar Expert Posts: 30
    I have not gotten a size for the pump, but that is a valid thought! I should ask as soon as I can.

    unseenone said to buy the best I can afford. I can afford any of the options but I'm not sure which is "best". It would also be easier to not have to "afford" the geothermal as it is quite a bit higher than the other options, but doable if it is the best long term choice.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    Catscratch wrote: »
    I've posted before when we were trying to decide if we wanted to deal with an electric company and a $50k+ hookup, or go off-grid. We ended up getting a territory swap with another electric company and paying $12k total for the install (we stopped considering off-grid at that time). The help we received from this forum was extremely valuable though and I'm back for more advice!

    We are looking at our HVAC now. We wanted geothermal but after drilling a hole found out it was going to cost considerable more than planned. So now I'm playing with options:
    1 - 14 SEER unit with about $4k of solar panels.
    2 - 16 SEER unit with about $2k of solar panels.
    3 - Go ahead and spend the extra for Geothermal. We would get 30% tax incentive for total install cost, but it would still come out considerably more than the other two options.

    Part of my reasoning for this is the 30% for solar install and also PV will help with ALL the appliances in the house where geo would only help with HVAC.

    Any opinions from you guys? Experience? I live in Kansas, it get's hot in the summer and cold in the winter if that helps any. Also a long term living arrangement, we plan on living here for 30yrs or more (until they drag me to a home). Ultimate goal is a cheaper utility bill...

    Thanks!

    As bill said look at those 27 SEER units. I have been doing some electrical work for a guy who does HVAC design and he has been using those in some of his rental units. One space as one as its sole heat source. We are in upstate NY so its cold here. IIRC electricity use wise, around 27 SEER is equal to resistance heating at 0 degrees F. Geothermal (or ground source heat pump I think is a more correct term) is certainly more efficient as you are dealing with a much lower delta T from your target temp. Around here you want to get around 8 feet down - you can go less of course but that is where it starts to stay pretty stable and above 40. I would think if you were burning fossil fuels for heat, going ground source heat pump would be more bang for your buck than PV.
  • Catscratch
    Catscratch Solar Expert Posts: 30
    The wife doesn't want anything to do with minisplits. She just didn't like them when her work had them.
    I can get a 2kW PV system for $4k total, then claim the 30%. But the 14 SEER part of it will not have a rebate. The ground source will be 30% on total cost.
    The ground source is looking like the better deal long term but the initial cost is spooky!
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    Catscratch wrote: »
    The wife doesn't want anything to do with minisplits. She just didn't like them when her work had them.
    I can get a 2kW PV system for $4k total, then claim the 30%. But the 14 SEER part of it will not have a rebate. The ground source will be 30% on total cost.
    The ground source is looking like the better deal long term but the initial cost is spooky!

    I depends a lot on if you just hire it out or do some of it yourself. You could rent an excavator and dig a ground source trench yourself for a few grand, or hire it out for ?????. There is the well method too. I guy I know did 4 300 foot deep wells. I think he spent 80 grand on it yikes - but now he saves $4k a year forever (total guess on the dollar figure).
  • Catscratch
    Catscratch Solar Expert Posts: 30
    ROCK! Our basement was dug with a giant steel ball that they dropped onto the rock several times and then scrapped out the rubble. Digging a trench isn't going to work. This is one of the reasons that we started to reconsider; the price went up due to having to do wells instead of a trench. Then we drilled a well to see if we could do an open loop. 180 feet deep and sat over night. We were hoping for 8 gallons/minute and we got a quart in 12 hours. So now we are looking at 4 wells at $7500 total for drilling. I think this is a great price for drilling though, and total investement for ground loop heat pump should be around $20k - 30%.
  • unseenone
    unseenone Solar Expert Posts: 61
    While you are engineering the system, and seeing as budget is no issue, why not do both, then you have options.
  • Catscratch
    Catscratch Solar Expert Posts: 30
    Lol, I wish budget was no issue. The ground loop heat pump (geothermal) would max us out. The 14 or 16 SEER system combined with solar would end up costing a little less initially than geothermal but wouldn't have as high of a tax credit as geothermal. Dollar for dollar I'm not sure what the best investment is: spend $20k on geothermal and get $6k back for a total of $14k spent, or $9k on an air to air heat pump and $4k on solar (getting $1200 back) for a total investment of $11,800. In the end they aren't much different so which is the better system? They are only $2200 different, spread out over the next thirty yrs it isn't much...
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    you need to compare the savings or reduction in outlay over , say 10 years, that each system will give you, at current prices and then figure it out with a 5 % rise in payments every second year, that increase is a conservative one, locally they have been applying to the Commission or a 25% over ~ 8 years but got rejected for the immediate future and got 10% over 5 years IIRC.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Catscratch
    Catscratch Solar Expert Posts: 30
    Our local provider has increased rates 22 times since 09'. I guess that only increases the value of the most efficient system, because they aren't going to stop asking for rate hikes.
    Thanks for the opinions guys.
    Still waiting for the HVAC guy to get back with us and give numbers.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    I would keep my mind open to an air source heat pump like a mini-split. You may have got a bad impression based on a poor unit.
    I have had clients tell me something similar and after I spend some time explaining how expensive it is to do a ground source, and the problems that can come up they start opening their minds.
    Most of my experience with passive solar for conditioning space is from about 7 years or so back. I do not have any recent experience because it is an old tool I no longer need thanks to split heat pumps.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Catscratch
    Catscratch Solar Expert Posts: 30
    Help me understand the mini splits. We will have a full basement and ground floor. The ground floor has a main room that is mostly a single room with vaulted ceilings. There is a bedroom, two bathrooms, and a utility room to the side of the main room. These rooms are walled off from the main room. How would mini splits heat/cool these areas when the doors are closed? Would the bedroom and bathrooms lack conditioning at these times?

    Thanks for the help.
  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    Mitsubishi just came out with a mutizone minisplit rated for cold climates. One outdoor units and a number of indoor units. They are inherently space units so you need a head unit in every room you need HVAC
  • Catscratch
    Catscratch Solar Expert Posts: 30
    Geothermal isn't going to work. More consulting with the HVAC guy has uncovered enough extra cost to keep us from going that route.
    We are now down to 2 choices:
    1. Upgrade insulation to closed cell foam and install the cheaper HVAC system.
    2. Install the cheaper HVAC system, regular fiberglass insulation, and about 3.5kw worth of PV panels.

    Not sure which is the better option. I've read great things about closed cell foam and it's sound proofing of the house and reduced utilities. But the PV option would receive the 30% rebate and reduce utilities also.
    I've never lived in a new house before so I really don't know if a well sealed fiberglass house "feels" any different than a foam house. If the reduction for utilities is the same for both systems I'm not sure which is the better choice. We do live in a windy place so that might factor in to the decision.

    So, once again I'm asking for advice or experience...
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Part of the 'new' house system is an air barrier under the siding, also called 'house wrap'. Does this house have it? If not then closed cell would probably be better as long as you use inject-able foam to'seal' around the rigid foam...
    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Catscratch
    Catscratch Solar Expert Posts: 30
    Yes, it has house wrap. It is being installed this week. Our builder prides himself on air infiltration, he claims to do an excellent job at minimizing it. The house is still studs on the inside and I have time calk everything if I want. I've already done some of the spray can foam around some of the more obvious spots. I'm just unsure if it is worth the extra $$$$ to spray foam it, or just go with the fiberglass.
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Catscratch wrote: »
    Yes, it has house wrap. It is being installed this week. Our builder prides himself on air infiltration, he claims to do an excellent job at minimizing it. The house is still studs on the inside and I have time calk everything if I want. I've already done some of the spray can foam around some of the more obvious spots. I'm just unsure if it is worth the extra $$$$ to spray foam it, or just go with the fiberglass.

    I don't know if you are planing a 2X6 construction or not but one alternative to keep foam cheaper is to use about 2 inches of foam and finish it off with fiber glass bats. It then provides the sealing of foam and holds the cost down.
  • Catscratch
    Catscratch Solar Expert Posts: 30
    solar_dave wrote: »

    I don't know if you are planing a 2X6 construction or not but one alternative to keep foam cheaper is to use about 2 inches of foam and finish it off with fiber glass bats. It then provides the sealing of foam and holds the cost down.

    Our insulation guy is going to do a cost analysis of this very thing on Wednesday...
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    the sealing around the framing of windows and doors is most important, I did it on our place and even without the vapour barrier on the inside once the windows were in and 1/2 of the insulation was in, double 2x4 walls,we were very comfortable last OCT NOV when it was ~ -15 C (just above Zero *F) and the other place that is critical is along all the plates, top and bottom and corners. I used DAP ELASTOMERIC sealant, has tremendous stretching ability and good inside and out...

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Catscratch
    Catscratch Solar Expert Posts: 30
    I talked with our builder yesterday. We decided a 14 seer unit is the best option. Then we talked about whether to just do conventional fiberglass insulation with extra care on calking, full closed cell foam the walls and roof, foam on the roof space only with fiberglass in the walls, and foam roof and a thin layer on the walls finished with fiberglass. Foam will lessen the tons of the unit,reduce utilities, and make for a quiter house. I've also read that bugs and mice will never burrow through it (which will be nice as we are very much in nature).

    If we go with fiberglass we will buy about 3kw worth of solar panels. If we decide foam is needed then we will not be able to afford pv panels...
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    the sealing around the framing of windows and doors is most important, I did it on our place and even without the vapour barrier on the inside once the windows were in and 1/2 of the insulation was in, double 2x4 walls,we were very comfortable last OCT NOV when it was ~ -15 C (just above Zero *F) and the other place that is critical is along all the plates, top and bottom. I used DAP ELASTOMERIC sealant, has tremendous stretching ability and good inside and out...
    ADD, the type we used has a paper cover on each sheet and is 'directional... re application
    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    My only comment would be the lower SEER rating. If you expect electric power to go up in price, or you ever want to go off grid, a higher efficiency unit may be worth the money now.

    In California, I am already paying $0.30 to $0.40+ per kWH for sunny summer afternoons (I don't have/need A/C in our climate)--But they are really looking at raising energy costs (for fuel costs, "going green", etc.).

    Another thing that may be coming to many folks is the issue of billing. In the "olden days", we pay $4 per month connection fee and $0.10-$0.40+ per kWH for power.

    In the near future, it may change into a $40-$100+ per month connection fee and $0.5-$0.10 per kWH for electricity. This makes many conservation and GT Solar systems very cost questionable...

    And for folks out in the sticks, high monthly charges with relatively low kWH per month usage (call it less than ~500 to 100 kWH per month), it could be cheaper to disconnect from the grid and go with full off grid solar (we have had a person here with a cabin--Ended up being cheaper to install a small solar system + genset for weekend use than to pay the monthly connection charges).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Catscratch
    Catscratch Solar Expert Posts: 30
    I was all for a higher efficiency unit until; I ran some numbers, our HVAC guy ran some numbers, and a life long friend who has done HVAC forever ran some numbers. The general concensus was something like $2/month savings. It would basically never pay back. I'm very concerned about increasing utility rates which is why I'm putting so much effort into this process. Unfortunately I don't know the answers in my situation, but I am learning an awful lot right now!
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    You have to consider amp/load.

    A 14seer condensing unit will consume between 25~30amp loads, 2~2.5tons.

    A 16seer condensing unit will consume 30~40amp loads, 2.5~3tons.

    If you have solar on the roof, it will reduce attic temperatures, so a seer 14 is more practical and will use less power. Based on a sq/ft exceeding 1500sq/ft of home the seer 14 will run longer in duration than a seer16 but when the load is 1/3 less than the seer 16 there is a 25% savings across the board.

    Also note if you are grid tide and are solar there is voltage rise through out the home so the lower seer will actually function more efficiently than it's specs with less chance of voltage drop at start up.
  • Catscratch
    Catscratch Solar Expert Posts: 30
    Based on a sq/ft exceeding 1500sq/ft of home the seer 14 will run longer in duration than a seer16 but when the load is 1/3 less than the seer 16 there is a 25% savings across the board.

    I'm not sure I understand this part of your post. Which is going to be 25% savings, the 14 seer or the 16 seer? Is it the 14 seer because it consumes 25-30amp loads instead of the 16 seer at 30-40 amp load (even though it runs longer at a time)?
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Yes you can see a savings in seer14.
    There is a potential thresh hold in that savings after 1500sq/ft.
    Let's say you are using a seer 14 for 1800sq/ft. The home would require high standards for insulation.

    When condensing units consume more than the loads produced by solar it can be a never ending battle of losses.

    If you have a 200amp main service you are allowed 40amps of back feed solar. In this case you are not going to want a seer 16 that may require 40amps of consumption. It makes investing a zero sum game, there is no true investment, and always fighting losses.

    Engineering and designing around a solar system, and being confined to the 120% back feed rule. The design factor is to ensure that all devices in the home at any given point in time in a 24hour time frame will consume less load than the maximum load solar will produce at maximum solar insulation.

    If you eventually want the utility company to pay you out credits, instead of you owing credits annualized, it's the only formula to follow.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Note, for some folks, you can install a 200 amp panel with a 175 Amp main breaker (for example, if your code allows) and that lets you put in a 65 amp total of GT solar (over the 40 amp "simple" 200 amp service limit).

    Yea, lots of tradeoffs... If you have a good HVAC person--Then you should be doing well on figuring out the best bang for your buck.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset