To echo KY, HEPA filtration is the best. Units sold for this purpose residentially, are usually self-contained, have their own fan and typically only filter between 15-20% of total air being conditioned by a forced air unit. Reason being, residential blowers on units canÂt handle the excessive static pressure required of these filters. Commercially, class 1,000-10,000 clean rooms typically have the HEPA filters installed integral with the ceiling diffusers. Because of their inherent restrictive airflow rates, the amount of diffusers is normally 5-8 times a standard residential system to get the supply air back to the space. In addition although a standard residential furnace or air handler can be used, a booster fan is installed in conjunction to move the air through the filters. The benefits of this system is that the conditioned air if filtered at the highest known efficiency rates known just before entering conditioned space. As mentioned earlier, positive pressure is a key part to keep the conditioned area clean with reduced infiltration. These systems when done right are the best yet, expensive. Depending on how much area and how clean you want it to be, there can be many ways to do this. Any type of electric air cleaners can and do produce some levels of ozone so, as stated, you do need to stay away from any type of these. Perhaps if you donÂt need the ultimate in air scrubbing, a dedicated, sealed combustion unit, furnace, air handler w/heat pump or boiler with radiant panels, stay away from finned radiation as they harbor dust, or radiant floor would be a great option. You could then use one central HEPA unit or the Honeywell stand alone HEPA units work well to supplement or use in designated areas. God Bless

Yeah, I thought about some kind of pressure test, but from what I could tell, it would have taken some extensive repair work just to put the system back to a loop of some kind worthy of being tested. So, it's too late now anyway. The Base Board is gone. It really was a mess, and if I ever want to, I could always add some clean new radiators or base boards to the rooms that need it. That being said, I have a decision to make: Option #1 - Variable Speed Air Handler Model#FE4ANF003Twith a 3-Ton, 16 SEER 2 Stage Heat Pump with Air Conditioneing Unit Model#286BNA036. Option #2 - Variable Speed Air Handler Model#FE4ANF005Twith a 3-Ton,20 SEER Inverter Heat Pump with Air Conditioneing Unit Model#280ANV036 Both Systems Equiped with Evolution Zone Controls for 2-Zone Heating and Cooling System. 15 KW Heat Strip ect. Option to add Humidifier and Media Filter +$1,000. The installer did an operating cost analysis and it showed the Extreme System (20 SEER) being just a bit better in cooling, but $900/year less in heating. Which to I pick?

Where abouts in "Central California, coastal inland"? The microclimates there chage quite extensively so a more detailed location would help. Can't imagine it ever freezes there(?) This is important because of the high summer temps and low winter temps. If you're in the desert, you won't have much of an issue with humidity but if you are on the coast, this may be a factor.

I'm disappointed that what had at first seemed a very balanced comment was followed by what seems to be misinformation and misdirection. People buy ground source heat pump equipment because they want to and can afford it. Or decide they need to in their locations. They're hugely more expensive than alternatives, which is why they're still not very common. "When’s the payback on a Tesla? People still choose to buy them for reasons other than the ‘bottom line’." Not a comparable. A false analogy. "I would not choose natural gas or propane for reasons relating to the environment, safety, IAQ & paying for yet another utility hookup for an energy source that might not even be used for months on end during the year." What effect having a gas furnace has on indoor air quality. Another hookup? Most people prefer gas cooking appliances and besides, the OP is talking about an existing home, he either has gas service or he doesn't. "Rather than spending perhaps tens of thousands of dollars on a Solar Array, I would sooner invest that same money, hopefully less, in a ground loop for a Geothermal system." Sure you would, that's the business you're in. The ground source heat pump market is not growing as expected by those in the industry, which suggests that your opinion isn't widely held or easily sellable. In many parts of the country, solar panels can have a quick payback. Not so ground source heat pumps. "I often hear about Solar Panels when geothermal is mentioned, as an alternative way to save money by creating energy." In a place like Texas, where electricity is cheap (other than during cold weather crises as they just experienced) there's likely no payback from a solar panel installation. People do it as a personal statement, call it for environmental or other personal reasons. Like buying the Tesla, not a financial decision. An HVAC system blows warm air when it's cold, cool air when it's hot. It's one of those things people don't care about - either it works or it doesn't work. Spending extra money for an exotic system doesn't equate to extra payback when the home is sold. Neither owners, nor visitors, nor people passing by, nor anyone else, concern themselves with what's doing the work. It's equipment that doesn't produce an experience for someone in the house if it's working. In the US, there are vast areas where electricity is cheap. It will remain so for some time. People don't spend money today to potentially save money 10 years out when market conditions may or may be different. I suspect you could build a house with mahogany or teak framing. Or you could paint the framing bright colors. Why bother, you can spend less money and effort and get something else that will do the same job. "We almost never use setbacks at our home - even when going on vacation for weeks on end with no one home, our geothermal just runs." You're combining two different things to produce confusion. Thermostats that have a setback feature ALL are set up to provide lower overnight temperatures to have more comfortable sleeping conditions and then a recovery in the morning before wakeup time. As sleep specialists recommend. That in demand comfort features isn't possible with ground source heat pumps because the warm up period from a setback is too slow to be convenient to use, absent triggering a secondary heating source (like a furnace) to help. THAT'S why you don't "believe" in setbacks with a heat pump - they don't work. Turning down a thermostat during heating season when the home will be unoccupied is not a "setback" as that word is most commonly used. It's done to save money, why heat a vacant house? No setback thermostat is needed, even a dumb 50 year old analog thermostat can be turned down.