I have a two-story home with separate HVAC for each floor and am seeking a geothermal system for the first floor, app. 1000 sqft. Based on my research, St. Louis does not offer a lot of choice on experienced geothermal installers (would be happy for someone here to provide me wrong). I have several bids and have narrowed the field to two providers, which I'll call Experience and Budget: 1) Provider #1 - "Experience": $37.4k - Geocomfort 3 ton GYT036 - April Aire M-13 air cleaner - Aprilaire Bypass Humidifier - Air Scrubbers - Geocomfort desuperheater - 40 gal. Bradford and White Energy Star gas water heater and expansion tank - 50 gal. pre-heat tank - 3 x 200’ grouted wells - Honeywell IAQ thermostat - Flue liner for water heater (exhaust gases from the water heater exit through an adjacent chimney) - Electrical and intake mods, excavation, labor, permits, & inspections - 10 year parts, 1 year labor warranty 2) Provider #2 - "Budget", Proposal #1: $25k - Water Furnace 3 ton LDV036A1114CT - 3 x 150' grouted wells - Labor and connections (not including electrical wiring) - Does not include electrical modifications, no intake mods needed - Permits and inspections - 10 year parts and labor warranty 3) Provider #2 - "Budget", Proposal #2: $34k - Water Furnace 5 ton NDV0646111CT - 5 x 150' grouted wells - Rest same as #2 Provider #2 gave a third option for $48k with a Water Furnace 7 (NVV060111CT) + duct mods to handle increased volume, but I didn't really take this seriously. Some on this forum use a Water Furnace 7 to handle 3k-4k sqft. houses, so I think I was just put on there as a money grab or to create extreme contrast with their other two proposals. A Water Furnace 7 looks like serious overkill for 1,000 sqft., even if its variable compressor means fire-and-forget. The two providers were dramatically different. Provider #1 is a decades-old HVAC provider coming from an engineering background, and so their emphasis is on high quality design and results. For instance, Provider #1 insisted that 200' wells were most appropriate based on climate zone extremes and decades of local install experience. Provider #2 is a green tech. HVAC company less than 20 years old. They proposed several Water Furnace options, without necessarily considering whether they fit well. It's plain this forum tends towards Water Furnace over GeoComfort. There's a $12k difference in price between proposals #1 and #2, but this distance shrinks to ~$3.5k if one considers the #1 includes a water heater, desuperheater + exp. tank ($2-3k), flue liner + install ($2.5k), full-service electrical and carpentry work ($1-1.5k), and air scrubber + humidifier ($1.5k). Bottom line: St. Louis doesn't appear to offer a lot of geothermal competition, so this appears to be a classic Budget vs. Experience choice. Provider #1 is clearly more experienced, but is the extra cost worth it, especially considering that I've seen 3 ton systems with similar accessories in the $28-32k range elsewhere on here? Or should we go with Provider 2's $25k proposal and add accessories, figuring that the generous warranty will cover any provider shortfalls?
I would want to use the installer with the most experience, best understanding of geo technology, and most attention to detail. There are many things that need to be done correctly for an efficient geo installation. You want it done correctly the first time. You don't want to rely on a warranty to correct installer's mistakes. What's the explanation for offering either a 3 T system or a 5 T system for the same application? The space should require a certain size unit, so offering two units with such a large size difference doesn't make sense. That would steer me away from that provider, unless there was a logical explanation. Ask your installer to do a load calculation on your house and show you the results to make sure you are installing an appropriately-sized system. Three tons sounds like a lot for 1000 SF. I'm using one 4 ton unit for a 2900 SF three-level house. Also ask them for a pressure drop analysis for the loop and what pump they intend to use. You want to make sure they know how to design the loop and appropriately size the pump for efficient pumping. Wha about backup heat? Are they proposing heat strips?
you can't size a system (specify a tonnage) if you don't know the house's heating and cooling load. I'm guessing St. Louis may have more of a cooling load or about even heating/cooling. Ask both of them how they came up with the tonnage of the units for each quote? The tonnage of the unit is directly related to what your house needs to heat and cool it. Further to this, #2's quotes make no sense. If your house needs a 3 ton unit for its heating and cooling load, then that should be what gets installed. Getting a 5 ton unit would be a waste and not an upgrade not to mention the likely hood of short cycling/poor humidification during cooling for a single stage unit if in fact you only needed a 3 ton unit. Also, that 3 ton unit (assuming this is the right size) needs a certain amount of bore length to properly exchange heat with the ground. Ask them how they came up with the number of bores and length. There would be no reason to have one option of 3x150 and another option of 5x150. The 3x150 might be undersized; 5x150 seems like extreme oversize for no benefit to you. It occurred to me that maybe your interpretation of #2's quotes is wrong?. Waterfurnace has 3 common model lines - 3, 5, and 7 series. That has nothing to do with tonnage - the differences between the 3, 5 or 7 series comes down to single speed, dual speed, or variable speed compressors and fans as well as various other upgrades/options. Within each of those series, there are various size units (tonnages). So you can have a 3 series 5 ton unit or a 7 series 3 ton unit or a 5 series 4 ton unit, etc. Are you sure you aren't confusing the Waterfurance series nomenclature with the unit's tonnage and vice versa? If there is no confusion and what you posted is accurate, then run from #2. They would appear to have no idea what they are doing. I don't know anything about Geocomfort but #1's quote strikes me as logically put together. I personally have Waterfurnace 7 series units. I had 5 series units quoted but the savings of the 5 over the 7 didn't justify how much better the variable speed compressor/fan units operate. Glad I went with the 7 series. Price shopping for geothermal work tends not to end well. Just read this forum for a while.
@gsmith22 @SShaw Thanks for your comments. First, I should add that, even though the 1st floor is 1000 sqft. both providers are calculating load with the foundation slab basement too. That adds another 500 sqft, so 1500 sqft (other half of the foundation is an unconditioned garage). My bad. Provider #1 said that, based on his experience, systems run on average ~650 sqft/ton of heating, so 2 tons might work but would be cutting it close, especially in the winter, since we're using the system for hot water too. Provider #2 said that Proposal #1 (3 ton 3 Series) is a 'base' proposal that 'undersized' for the heating load but provides full cooling load. Proposal #2 (5 ton 5 Series) fully covers heating load. Proposal #3, the one I didn't post, is for a 5 ton 7 Series. Both providers saw that we already had a 3 ton AC installed. No, neither Provider did a Manual J load calculation, although Provider #1 has offered to. Backup heat is a 15 kW electric blower. Pressure drop analysis and pump question - good suggestions.
Choosing between a smaller heat pump that covers only the cooling load or a larger unit that covers the heating load is a reasonable tradeoff. I replaced a 3.5T ASHP and 80,000 BTUH oil furnace with a 4T 7 series. The 7 series is supposed to cover 100% of the heating load. There are a couple considerations with this though. First, the 5T 5 series on low cool is about 50% more capacity than thee 3T 3 series on high, so it could be oversized for cooling. I would want to compare the heat pump capacities to a Man J to make sure the units are an appropriate fit. The 4T 7 series could be a better fit for you, since it has about the same heat output as the 5T 5 series, and can go down to 27% capacity, which would allow it to match the cooling load. Second, your ductwork is likely sized for your current 3T AC and might not be able to move enough air for a larger unit. You should ask your installer to measure the size of your supply and return ductwork to see if it can handle the airflow from a 4T or 5T unit.
A few thoughts: 1) In general, an experienced contractor knows what it takes to make a customer happy. I refuse to go cheap since it likely results in lesser happy customers. 2) #2 is odd. Common sense tells you that you don't need a 5 ton for a 1000 sqf first floor. Especially not in Missouri. If you do, get an energy audit and fix you leaks in the house envelope. 3) It is hard to understand that if you have the voice, not to invest additional money into the 7 series given its superior perforce, comfort and efficiency. 4) I am bias, we are a Waterfurnace dealer and install them. But they are that much better than other products. You can get a 3 ton 7 series if you want, but I don't understand why you don't get whole house solution including your second floor? Maybe you can elaborate. But also a 7 series need skills and know how to install to perform at a high level. One thing does not work with geo: Getting multiple bids and going with the cheapest one. Sometimes as always with new technologies, old established companies cannot compete with newer technologies with new "young guns". Older companies do not understand efficiency, and would not even know how to setup the 7 series properly so it can perform.
Thanks @docjenser . We aren't going with the second floor because it has an entirely HVAC system - electric forced air + different set of ducts. That would require an additional split or package system (bottom half of split in the basement, top half upstairs OR package upstairs). Provider #1 had provided a quote for both systems at first, but it's just not possible right now. We actually have 1500 sqft to condition, including the basement. Knowing that it's impossible to perform a Manual J over the Internet sight unseen , would you say that 2-3 tons is probably more appropriate for that size of space than 4-5 tons? Thanks again.
I don't know. Normally, unless you have a very leaky house, 1500 sqf sounds more like a 2-3 ton than a 4-5 ton, especially on a single floor with another conditioned floor above it. I changed over the years, with the arrival variable speed technology. I now design for the whole peak load, without supplement heat. In the grid of the future, we simply cannot afford to have all the heatpump going into supplement heat all at once at the peak heating hour. What are your loads? What was your previous consumption?
