Georgia HELP doing an addition will my unit handle it?

Discussion in 'Maintenance and Troubleshooting' started by Hoop2845, May 9, 2020.

  1. Hoop2845

    Hoop2845 New Member

    First of all let me say that I am so happy that this group was established for people like me. I am new to Geothermal and have a question I need some advice on.

    We bought a house last November with an Open Loop System that works off a well. The unit is a 3 ton Bosch system.

    We have a 1800 square foot brick house that has 900 up and 900 in the basement. The basement is fully exposed on the North side (sliding glass doors on the entire side), the other 3 walls are underground.

    We are doing an addition upstairs adding another 900 square feet. Once this addition is done we will only use the basement a few times a year for company.

    What we are wanting to do is put in a different HVAC upstairs that would cover the original 900 sq ft upstairs and the additional 900 sq ft we are adding.

    I understand that the system would really be oversized for 900 sq.ft. But, my question is, can we run that Geothermal System on just the 900 sq feet in the basement without hurting the equipment. Like I said earlier it would maybe be ran 2-3 days a month max.

    If that would not be feasible do you think the current unit would carry the additional 900 sq ft we are adding. Taking into consideration that a third of the square footage is in the basement and not used year round.

    Heating /Cooling: 900 sq.ft
    Unit: Bosch
    Size: 3 ton
    Location: Milledgeville, Ga.
  2. Deuce

    Deuce Member

    I think the existing unit could handle the AC summer load because the basement should stay fairly cool, but the heating load in the winter would be harder. You will need to get ducts up to the new floor. I would say if you could add the new floor and remove or have a way to use a damper to close off or just provide minimal HVAC to the basement you might just need a mini split for the basement.
  3. arkie6

    arkie6 Active Member Forum Leader

    I would look at using the existing geothermal unit to heat/cool the floors used regularly and maybe add a 9000 to 12000 BTU mini-split to heat/cool the seldom used basement. I would keep at least a small part of the existing ducting (supply & return on opposite ends) to the basement to help promote air turnover (say 50-100 CFM) to keep the air down there from getting stale and help keep humidity in check when not occupied. Most mini-splits also have a de-humidification mode that would likely be useful in a basement in the south in the summer. Another option to consider is a heat pump water heater located in the basement which would provide essentially free summer time cooling and de-humidification for that area.
  4. Hoop2845

    Hoop2845 New Member

    Deuce and Arkie6,

    I very much appreciate your replies. It gives me some hope that we can maybe use our existing system and use a mini split for the basement. As to the heat pump water heater...I’d never heard of such a thing. Did a little searching and that sounds like almost a tailor made solution.

    The existing geothermal system is in a closet on one end of the basement so if we relocate it, that’s where the heat pump water heater would have to go. We currently have a tankless water heater on the outside wall of that same closet. We were planning to put a water heater in the attic because the areas that will have the most hot water usage are on the other end of the house and in our new addition. It already takes a good three minutes to get hot water at the kitchen sink and that will only get worse for the new addition. Maybe use a recirculation system on the hot water? I’ve heard of those but have no experience with them.

    Concerning the mini split...there are three bedrooms downstairs that would need to be conditioned. Would I need to have wall unit, or separate system in every bedroom?

    Thanks All!!

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