New member to the forum here, but I’ve been reading the community’s posts extensively for the last few weeks ever since the wife and I began gaining quotes for geothermal HVAC upgrade for our aging standard equipment. We have weeded down a number of quotes down to two established geothermal companies in the area, but we’re stuck on best way forward. We’re hoping you can help us across the finish line. My apologies for the wall of text coming. Home details: 25 miles NE of Baltimore, MD. 2003 build. Above grade: 4385 sq ft (5632 sq ft including finished basement), 6” external walls, double pane windows, R-30 attic insulation, probably Rockwool on exterior walls, 9’ ceilings throughout home, 18’ vaulted ceiling in living room with a large amount of north-facing windows, and vaulted ceiling in the bedroom. The home currently maintains temperature well - with the exception of the west-facing bedroom that appears to take a lot of thermal loading in the summer months and is a few degs hotter during the afternoon. Current equipment: Installed 2003, 1st Floor/Basement: 5 ton conventional AC/Natural Gas Furnace (in basement). 2nd Floor: 3 tons (or 3.5) AC/Natural Gas Furnace (in attic). Current energy cost is approx. $0.13/Kwh; natural gas: approx. $1.30-$1.50/therm. Water heating costs ~$30/month (natural gas + powered exhaust). We currently offset the temperature in the 1st/2nd floor 5-8 degs during the days/nights to primarily condition the floor we’re on. Quotes: Both companies are geothermal installers primarily; IGSHPA accredited; and have been in business for 20+ years. From what I’ve read in the forums, both quotes seem fair-to-good given the system size. Both companies have good online ratings overall. - Company 1: 8-tons installed; 160ft/ton vertical loop; 4 bores @ 320’, 1.25” pipe, grouted System 1 (1st floor/basement): Waterfurnace 5-series, 5-ton dual capacity unit (NDV064); Intellistart; ECM fan; 10 kW aux electric heat System 2 (2nd floor): Waterfurnace 5-series, 3-ton split unit (NDZ038); Intellistart; matching Water Furnace high efficiency air handler; 10 kW aux electric heat. Additional: Advanced Aurora Control System; Performance Monitoring, Energy Monitoring, Refrigeration Monitoring, flow center, thermostats, Symphony Aurora Weblink, and water alarm Cost: $56,000 installed gross (pre-tax incentives); free 12-months same as cash (no origination fees) Geolink summary: Heating Load - 73,600 Btuh, Cooling Load - 48,800 Btuh. Internal Gains - 13,205 Btuh. Colling Temp Dif - 17 degs. Winter design - 13 degs. Summer Design - 94 degs. Heating Setpoint - 70 degs. Cooling Setpoint - 72 degs. Geolink projects zero (0) Aux heat usage, high speed cooling, or high speed heating annually. Geolink projects 84% geo run time on hottest days annually, with ~10-12k of geo air Btuh’s availabile over the Load Space Btuh calculation. Coldest days are 94% run time and ~4k Btuh available over the load calculation. Option: Upgrade 5-series, 5-ton NDV064 to 7-series: $4,900 extra Option: WaterFurnace Desuperheater with 50-gallon storage tank- $2,000 extra Company measured the square footage of the home before the quote. I did not see the sales rep measure windows specifically, but he may have accounted for them. He indicated he calculated a Manual-J to inform his 8-ton quote. The sales rep noted he sizes systems to run on the low compressor setting at all times possible; he also prefers aux electric heat vs fossil fuel aux/emergency heat as it was more cost effective. He asserted this sizing and aux setup would provide the best RoI over the long term, despite potentially needing a larger system to start. He also noted running in a lower compressor setting would reduce wear and tear on equipment over time. - Company 2: 7-tons installed; 160ft/ton vertical loop; 3 bores, 1,120 ft. of vertical bore, 1.25” pipe, grouted System 1 (1st floor/basement): Waterfurnace 5-series, 4-ton split unit (NDZ049); matching A-coil; Rheem 96% gas furnace; variable speed blower; 2 speed burner. System 2 (2nd floor): Waterfurnace 5-series 3-ton split unit (NDZ038). 2 Speed compressor with matching A-coil; Rheem 96% gas furnace; variable speed blower, 2 speed burner. Additions: Performance & Refrigerant Packages on both. Programmable thermostats Cost: $46,900 installed gross (pre-tax incentives); 12-months same as cash (5.5% origination fee - $2,600) Geolink Summary: Heating Load - 77,108 Btuh, Cooling Load - 81,080 Btuh, Internal Gains - 13,834 Btuh. Cooling Temp Dif - 20 degs. Winter design - 13 degs. Summer Design - 94 degs. Heating Setpoint - 70 degs. Cooling Setpoint - 75 degs. Geolink projects zero (0) Aux heat usage or high speed heating annually. 7% high speed cooling run time. (7% annual basically equals the hours in the top two temp bins) Coldest days are 100% run time. Geoair vs load Btuh are essentially the same in the coldest two bins (7 degs/1 deg; 13 hrs/1hr annually). Geolink projects 100% geo run time on hottest days annually (top two bins –92 degs & 97 degs; 72 & 6 hrs/yr). 2nd bin (92 degs) geo air Btuh is equal to load Btuh (~71k). Hottest bin (97 deg, 6 hrs annually) geo air is approx. 13.1k Btuh lower (in the red) than load Btuh. The owner indicated his calculations are very conservative. He noted my high cooling load Manual –J calculation is due, in part, due to the large bay of windows in my living room. I do believe Company 2’s Cooling Load Btuh calculation is conservative. Our living room currently has no issue maintaining temp at 70 degs (50% run time even with the 2nd floor temp at 77 degs) in the summer on our 5-ton, even without any blinds on the window. The only issue we currently have with temp control is our master the bedroom, which runs on the 3-ton system. Even running full-time, the MBR reaches 76 degs during the hottest days of the year. It and doesn’t cool down to 71-72 until 9-10pm. The 1st HVAC use limited impact on MBR temp. Option: Install Waterfurnace 5-series dual capacity unit (NDV049) with 10kh aux electric heat for system 1 and Waterfurnace (NDZ038) matching air handler 5kh aux electric heat for system 2 - $4,400 extra Option: Hot water assist with 50-gallon storage tank- $1,900 extra Company owner visited twice. He took detailed measurements of the home, including window sizing, during the second visit to inform the manual-J calculations. Owner indicated the initial HVAC was oversized, which is why he recommended 7-tons. He quoted for a split system with natural gas aux heat; he believed this provided the best up-front cost vs. lifetime system cost given utility costs in our area. I have an appointment this week to run through some different system scenarios (8 vs. 7 tons, lower cooling set point, deeper wells) with him to assure we can meet our performance objectives. I take it that many in the form do not find Geolink especially trustworthy. That said, from what I can decipher from the software both recommended systems seem viable. Company 1, as they indicated, is leaving headspace in the system to minimize usage costs (at a cost to us of $6.5k additional post-tax incentive). Company 2 appears to be tailoring a system to achieve a better install price point, with greater annual utility costs (~$150 +/- over Company 2). We initially were leaning towards Company 2’s recommended install as it would leave us with money to possibly use to do a solar install in a year or two. However, a number of questions are giving us pause the decision; this is where we're hoping you can come to our rescue. Questions: 1) Do you believe 7-tons will be undersized for our home? 2) Do you find notable cost/performance benefit by digging deeper wells vs. adding an additional ton of capacity. On the whole, if we needed to drill company 2’s 7-ton recommendation to 180-200’/ton vs. the current 160’ quoted would we save enough to justify not simply purchasing an 8-ton to start? 3) Do you forsee any performance or reliability issues with mixing a Waterfurnce split with non-WF air handler (Rheem in this case)? 4) Should we be worried with Company 2’s Geolink calculations on the hottest/coldest days? Do you believe cooling performance will be as potentially problematic as calculated if our 2nd’ floor cooling will remain on a 3-ton between our current system & both company offers? 5) If you believe an 8-ton approach is advisable, would you recommend a 5/3-ton setup, which currently match our home, or would an 4/4 setup provide better cooling performance giving the thermal loading we’re currently experiencing in our MBR? 6) Do you find the DSH+tank worth it in more mild climates? Also, do you see any performance risks for running DSH+tank on a split system with natural gas aux? The install price is quite significant given the limited RoI (~$100/yr). We are not inclined to make the purchase if it takes 20 yrs to buy back the difference. 7) From left field… Do you see any developments in the industry that will drive down costs enough to compensate for the loss of the tax credit at the end of 2021? (Can we wait until our current systems die and not pay substantially more than with the current credits?) 8) Is there anything we’re missing and should have asked? Thank you so much if you’ve made it to this point in the post! We thought we could work through the different options ourselves, but we simply don’t have enough experience to fully appreciate the differences between systems and any risks we might be incurring by committing to one company/approach over the other. We don’t want to spend more than necessary, but we will spend more money if we need to in order to ensure we’re not another geothermal install horror story.