Salam Hills , Cincinnati Ohio Gut Rehab -Heat Pump
The Need
"I am a local builder. I've built many LEED certified homes in the area. We are purchasing an older split level home to rehab and live in. We would like you to design the HVAC system for the home. We would like a heat pump if it makes sense or a multistage gas furnace. We plan to have a wood burning stove in the lower level, all l new flash & batt insulation thru-out the house in both the walls and ceilings..(no attic, 2x10 rafters only @ 2:12 pitch), and we also removed the black membrane roof and replaced it with a white EPDM material. The roof replacement will contribute significantly to the general ability to cool this place efficiently. New low-E windows will also be installed.
Typical Single Family Design Package
Manual J Load Caculation
Manual S Equipment Selection
Manual D Duct Design with 2 line Duct Layout
Ventilation Specfication
Conditioned Floor Area: 3358
Thermal Performance Design
White EMPD Roof: R-21 Cavity
Above Grade Walls : R-15 Cavity
Slab: NA
Infiltration: 4 ACH50
Windows: 0.28/0.30
Heating: 47,966 BTU/H
Sensible Cooling: 21057 BTU/H
Latent Cooling: 4580 BTU/H
Total Cooling:25,637 BTU/H
What We Designed/ Specified
When We Designed /Specified:
Heating and Cooling (Optional Auxiliary Heating):
Mitsubishi Electric-Trane 42,000 BTU/H Multi Position AIr Handler / 42, 000BTU/H Hyper Heating Outdoor Condenser
SEER2 15.4 EER2 9.8 HSPF2 9.3
Cooling MAX Capacity Nominal: 42,000 BTU/H
Cooling Min Capacity Nominal : 17,000 BTU/H
Heating @17° F: Rated 38,000 BTU/H , Max 48,000 BTUH 17° Rated -HSPF2 9.3, 17° Max -COP 2.1
Heating @5° F: 48,000 BTU/H COP: 1.9
Auxiliary Dehumidification /Ventilation– Santa Fe Ultra 120
Controls- Heating and Cooling Equipment controlled by Mitsubishi Kumo Cloud or wall hung thermostat. Dehumidification and Ventilaion have independent controls
What the Client Had to Say
Hey Jeremy, hope you had a great summer.
I want to say thanks again for the work you did on the design & specs for our home...it's really working out well. ................
Here's how the system performed since last November,
At the beginning in early Winter we had issues with the T-stat communicating with the air-handler, something about factory settings and min/max temperature variables..we Goggled thru it.. I didn't install the registers 'till January, and you could barely hear the fan when set to high...no vibration or hum, really quiet..all the rooms were well conditioned and evenly heated..the lower level studio was a bit cooler, but that was to be expected due to its location and flooring material, etc. we had planned on a wood stove in the studio from the very beginning. We would set the unit to 68, (fan on low) during the day, and 65 at night (fan on high)...very comfortable..no drafts or cold spots of concern.
Thru-out the spring we kept the windows open during the day & shut at night...and the fan on low most of the time...very comfortable..
The summer was a pleasant surprise..we would only run the AC during the evening..it would be turned off by 7am, and went back on at around 7pm..the house seldom got above 72 during the day, while we would set it at 68 for the overnight..again, we would run the fan on high for the night, low for the day...the interior was very comfortable..the lower basement door we left open with a manual 24" floor fan pushing the cool basement air up into the house for general circulation..we could've used a DH as you advised, but at the time we couldn't afford the extra $$, thinking the air-conditioned would perform that task..while the AC cooled the environment, it just couldn't get all the latent moisture out..even Auguste noticed it when visiting once,,,you could just kinda feel it in the air. We left space to add one at a later time with no significant modification to the ductwork, etc.
This Fall we've kept the windows open/shut as comfort allows, with the fan on low most of the time..like the Spring, its very comfortable with abundant fresh air..
As a reminder, we put all new flash & batt insulation thru-out the house in both the walls and ceilings..(no attic, 2x10 rafters only @ 2:12 pitch), and we also removed the black membrane roof and replaced it with a white EPDM material..this was a ginormous addition to the equation..this contributed significantly to the general ability to cool this place so efficiently. New low-E windows helped too.. we keep the lower level basement door open all of the time, along with the floor fan on medium..I've always kept my basement doors open with air circulating..something my father did as I recall. The system requires a fancy hi-tech thermostat, but we have it on manual settings cuz we can't figure out how to use all the fancy stuff.Overall the system as designed has worked out great.Lance came out and did a start up of the AC, and a cursory review of the system install, and it passed his approval...we've had no issues. The outside unit is super quiet and never seems to be working hard..the fans barely spin, even on the hottest days or coldest nights. We installed an A-O Smith, 50gal heat-pump water heater and it too is awesome..the only natural gas is our range and a gas grill on the patio..The house is a split level, with about 2900Sf over four floors and is essentially all-electric...our average utility bill is $165, and that includes the heat-pump water heater..I think our old house was 2100SF, with gas forced-air and tankless heater, with standard AC and the average monthly cost was around $300.. I think the all-in cost was around $32K if I recall. Mitsubishi makes a great product..the fit and finish of the air-handler and outside unit is impressive..heavy gauge components, well assembled and notably engineered..
In closing, what a great system you spelled out...it works efficiently and with minimum costs...I've definitely learned a few things on this install..I found it difficult to justify the cost on the homes I used to build, but it certainly makes sense on our own home...if I build another house, I will look into similar systems to install...
Thanks again Jeremy, and best of luck. Let's talk soon.
Cheers,
Chris
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