Adding A/C

Personal Finances Building / Maintaining a Home
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The prior note reminded me of our, maybe, next project…

New refrigerants… We are rumbling about adding A/C to our existing, relatively new Trane furnace… Need to call our guy next week, see about an estimate… He just replaced all out ducting to the latest, after a plumbing problem, and recently added A/C to my BIL/SIL’s home… So maybe he has time…

New unit will have the latest coolant, the Honeywell thermostat is all set, wifi linked… As good a time as any…

Quite a few days of steady heat this year, no major fires at least…

Time for an update…

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Consider minisplits - heat exchangers - as an option. May be more cost effective. The recent models, while reliant on a separate outside compressor, do both A/C and heat down to something like 15d F.

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Only, and main problem with mini splits is that the family room and bedroom(s) are on opposite ends of the home, and also leave out the living and dining rooms… So additional electrical work, as well…

Our ducting has recently been replaced, sealed, tuned for better airflow, so we’re looking at whole hour, all 1500 sf… Shouldn’t be bad, only a few weeks are hot, really, so far, but I can see where we’d get spoiled…

Sonoma County, CA, 30 miles inland… Evening ocean breezes… Whole house fan (noisy!) has been OK until now…

weco

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Contact from my Heating & A/c guy today, will be by tomorrow, Friday for a closer look at placement, power, etc…

He asked whether I had solar panels, we don’t, elec bill just doesn’t warrant it, but apparently there is a connection to heat pump systems, so we’ll see what that brings out tomorrow…

Rough guesstimate, about $7k depending on the ease or difficulty of the power connections… Or, if we are tempted to slip into a heat pump type setup… Only need a 2.5 ton unit, might be fun to find as manufacturers are shifting to newer higher efficient technologies… So we’ll see…

~1400 sf, coastal CA, foggy mornings, warm days, and sometimes that fog fails us, more and more lately…

progress…

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wecoguy in 2017 we moved into a 55+ Active Adult community. The only option was heat pumps. Not what I would have chosen, but every house has some compromises. Now I am very thankful. Local utility rates are local - but for us and also using national averages heat pump systems are less expensive than burning carbon and an AC unit. Initial equipment costs for a heat pump indeed are a bit higher. Summer AC costs us, in North Georgia, more than winter heating.

What has really made a difference is getting an inverter compressor that has more than two speeds (100% and 0%). Humidity is our summer killer. Our Carrier unit has 5 speeds ranging from 40% of name plate upward. Each step down from name plate increases the efficiency. As the system runs at lower BTU levels, the CFM of air across the coil decreases - more residence time since the coil temp is pretty much independent of BTUs. Longer residence time in the coil means a lower dew point for the air leaving the air handler. Bottom line our house is more comfortable vs the neighbors about 3 degrees higher in temperature. So not only is the cost per BTU lower, the number BTUs I need are lower.

Another item you may not know – the inverter units do not require those capacitors we seemed to be replacing at $30 plus a service call regularly.

If I were 20 years younger and did not live on a postage stamp sized lot, I would go crazy and go geothermal. Certainly not a money saver today, but I believe it will be over the next decades.

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It will be interesting to hear what my guy has to say about a heat pump system later today. I printed your note as a reminder as we discuss it, thank you for the info…

We’re still in our ~1400 sf home, where we moved in '74, lots of remodels, updates, but our coastal connection let us get by with just the whole house fam all this time, installed it myself, ridge and soffit venting lets the attic heat be blown out pretty well, but recent heat has extended to time frame of summer, or we’re less tolerant, so it’s time to change… Humidity is not a problem here, but can be controlled I suppose, we look at adding humidity, back when the Trane furnace came in, decided against it…

So we’ll see what’s up today, I see a variable speed condenser unit, maybe that’s what I’ll push for, so we’ll see…

https://www.trane.com/residential/en/products/air-conditione…

onward!

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If you want a variable speed unit get a complete new system. Have you ducting checked for size - it can be too big or too small. The reason is simple. All the cheap and easy efficiency gains have been made to meet current federal minimum standards. Just keeping an old air handler can lower the efficiency of a good heat pump unit to something like Builder’s Grade. Trane’s XV18 is close the the Carrier unit that I have.

If you are getting a unit with High, Lower and Off speeds, maybe you can keep some of your current stuff. But almost certainly you will have to have a new blower and main computer board.

I am from Michigan originally and I have been a natural gas furnace guy until this house. From 2002 until 2017 I lived in an Atlanta Pultee built development. Got close to a neighbor. We both had the High, Lower & Off systems. Natural gas heat and AC. His house was just under 2500 sq feet. Mine was 2850. As you might expect our utility bills were a higher. Our current house is heat pump and with a bonus room and conditioned sun room we are over 3000 sq feet. My heat pump system’s electric costs are lower than the electric plus gas in the Atlanta house. The Atlanta house had two 3 ton AC compressors. Our current house has a 2 ton and a 3 ton heat pump. It is rare for either unit to run at name plate level.

And when you get to these units, nobody makes a 2.5 or 3.5 ton unit. 2, 3, 4 & 5 tons. The units will run at a slower speed when ever it can. That is how you get 2.5 or 2.7 tons.

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Decision made!

We went with our guy’s recommendation, Trane is now American Standard, a 16 SEER 2.5T and opted for the heat pump model, not the vari-speed, he feels it is more complexity than needed, and a low profile/side discharge unit, in a different location than I had initially considered. Non-heat pump was cheaper, but we’re going towards reduced future costs, aka NG billing. Installed, ~$10K, $1300 less if it were the non-heat pumper.

I have an existing 30A 220v breaker pair, once intended for an electric dryer, comes close to the new location, should work out well.

My noise concerns were settled, non-heat pump was 70 db, heat pump is 71 db, so no noticeable difference. He thinks some added sound absorbent material may even reduces it more…

So this is a side discharge model, so is wider, but shallower since it’s between homes… a solid fence between will also absorb the sound, too…

Furnace, Trane, has to be raised ~20" to fit the evaporations coils under it as it’s a down flow…an ac outlet, and the doorbell transformer have to be moved out of the way, maybe I can do that ahead of time…

Just waiting now on start date, and away we go!

weco

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If you can plant some every green type plants surrounding the compressor - maybe 5 or 6 feet from the sides of the compressor you may be surprise how much sound they absorb. I don’t know what kind of native vegetation is in your area. We use things like Nellie Stevens holly here in north Georgia. Our actual plants if left unattended would get 20 feet tall and 10 feet in diameter. But by trimming them off at say 7 feet tall and 4 feet or so in diameter the foliage becomes very dense.

Your HVAC guy is correct - these units are a lot more complex. One reason we opted for this is my wife has a couple of different issues that make sleep difficult. A partial solution for her is lowering the bedroom temperature 5 or 6 degrees from the normal household ambient. That takes a lot of energy particularly in summer. So we have our house zoned.

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Well, new plantings are few and far between here, with the drought, cutbacks in even my drip system, some plants have already given up… And it’s a South facing wall, so, we’ll see how it goes… This might drive my neighbor into adding A/C too! 701 db is not all that loud, our TV likely exceeds that at times, Somewhere around here I do have a sound letter, an early Radio Shack tester, have to see where it’s hiding…

OTOH, we put up with their Jack Russel’s barking when they leave home, so maybe a little payback is in order… :slight_smile:

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This might drive my neighbor into adding A/C too! 701 db is not all that loud, our TV likely exceeds that at times, Somewhere around here I do have a sound letter, an early Radio Shack tester, have to see where it’s hiding… - weco

My GF has a db meter app she downloaded to her phone. I think it was a freebie. Sometimes we amuse ourselves in noisy restaurants by laying it on the table and watching the noise level dance around. Sometimes it hits 90+db, especially with a big group at the next table who have been drinking for a while.

PS - If 701 db is not all that loud to you, you may have a hearing problem.

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Hah! That 701 was a typo, thinking of 71, but also 70 db of the simpler unit…

Normal conversation is about that level, but our ears, even if younger cannot hear a difference of less than 3 db…

I likely have a db meter in an app already on my iPhone, yup, called SoundLevel, will do the job…

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but our ears, even if younger cannot hear a difference of less than 3 db…

This is a logarithmic scale - base 10 type. So an increase of 3 db at any point on the scale means the sound is 30% louder. I would expect normal people could say option “B” which is 130% of “A” is indeed different and also greater, not lesser.

5.5 hours a day at 80db is enough to cause temporary hearing loss according to my Apple watch.
1 hour and 45 minutes at 85db, 30 minutes at 90db, 10 minutes at 95db less than 3 minutes daily at 100db get the same warning.

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The human ear can detect changes in decibel levels, but the level of response is worth noting (Table 2.4). In general, a healthy ear would just about perceive a change in noise level of about 3 dB while a change in noise level of 10 dB would be perceived as an approximate doubling of loudness.

Table 2.4. Subjective Effect of Changing Noise Levels

Change in dB Level - Subjective Response
3 dB - Just perceptible
5 dB - Clearly perceptible
10 dB - Twice as loud

( https://www.sciencedirect.com/topics/earth-and-planetary-sci… )

There are tons of reference material out there, my education began when I took physics back in HS, Heat, Sound and Light is that text’s title, it’s still in a box in the workshop, I think, or at least the last place I meant to put it… In my many years at WeCo/LU, but mostly WeCo, we measures, set transmission levels for all the equipment we installed, Western made some of their own test equipment, but customers also bought their own, Ford/Philco tried to match HO and others, but Wandel-Golterman was the best in the world in the '70s… It had a scope, display, and frequency ranges from zero on into RF ranges, I could clip on the ironwork and tune in radio stations all around the area as their ground wave was sent out just as their air waves were… There are more signals, sounds out there than most imagine, some fit our audio range, but at my age, that has narrowed, moreso in my left ear, so I don’t buy stereos any more…

Anyway, I’d hoped to plop the new unit further away from my neighbor, but there are limits, so I’ll trade them my 70 db for their Jack Russell(s) barking I guess…

I may find ways to drop it a bit with absorbent stuff, my A/C guy, Brian has suggested a couple things, so we’ll work it out…

weco

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Had a chance to chat with my retired fireman neighbor, he’d seen my A/C guy the other day, so I laid out the planned setup… Not a problem. A not from my A/C guy told em he doesn’t want/need any up front money, just the total payment on completion… Progress¡

He’s already busy working on a remodel job, way too young, active to slow down… If I’d needed any electrical work done I’d have had his buddy, the one that swapped out my Zinzco sub panel a few years ago, do the work… Good people… I’d pass along all my conduit benders, pull snakes, but maybe not needed…

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Not long after the previous post, I received an email from my A/C guy, asking if this Thursday & Friday is too soon to do the work! I replied with “Come on Down!”

So I need to shuffle stuff out of the way so he has decent access to the Crawlspace, attic, and the unused 30A 220vac old dryer outlet…

Supposed to hit over 100 degrees over the weekend, so this is pretty timely…

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Call at noon today asking if they could get a head start today as they’d finished up the recent work early, sure! Came over, pulled the furnace, left the new coils in the garage, ready to hit it in the morning! Maybe they want to beat the weekend heat that’s coming! Great for us…

Also, was no need to get at the old dryer 22vac outlet, plan all along was to just cut/slice the run in the attic (boxed), So I wasted time moving stuff…

Progress!

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A bit of turmoil today as the A/C guys install the works… Snug space to fit the coils in under the last furnace, but with the 3 of us nudging, boss up in the attic lifting, my help holding, steadying it, it fit… Whew…

Access in the crawlspace to pop the coolant lines in didn’t work well, but a bit of a move to the side let it happen, so it’s in, brazed, ing evacuated, charges already…

AC power was a no-go as the builder didn’t run up and over to the dryer outlet, but sideways… So the fix was to use the old electric stove outlet, pulling it over meant only an added 10’ of 10 ga wire was needed… down inside the way, ready for power…

So no outside runs after all, and some patching, closing the attic access hole…

Doubt they’ll finish tonight, but it should be close… The worst is done…

Progress!

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It came, it ran, came to temp of 78, shut down… They’ll be back tomorrow to clean up the details, close the access hole, finish up… They have an early attic job, want to beat the heat, so we get to sleep in, evidently… Nice work! Busy guys on a busy day!

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A/C is done! All the details cleaned up, the various piping near the furnace/evaporator coil/water heater all reconnected, condensate drainage, etc… It’s a little different so I’m going to make up a well supported shelf over then, so we don’t stay cleaning stuff on them or the coolant lines, sturdy enough for me to stand on to reach the filter for changes… A cozy space…

Now with the heat pump A/C unit, the furnace will rarely even fire up, other than as the air handler, heat comes from the coils, not the NG burner unless it drops too low outside…

Brian was tied up, so no final billing today, per his son, but he knows where I live! :slight_smile:

Well done guys!

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