Washer/Dryer Energy Guides unhelpful/misleading

Weather forced a delay until today.

We popped the unit open and the first thing he noticed was that the evaporator coil was an aftermarket 4 ton (Summit) instead of a matching Carrier. The problem with that was that to install it they had to blank off about three inches on either side of the Carrier housing for this narrower A-frame. In looking at it and the furnace baffles his comment was, "builder standard"--as in cheap junk. He thinks that the narrow channel is the main flow bottleneck. He said that the Summit coil was sized as a retrofit into smaller, older low efficiency furnace set ups and although officially rated as 4 ton, shouldn't have been mated with the condenser and air handler in the system. Basically, it is a mismatch meant for a much smaller airflow in an SEER 10 system.

The fouling I expected to see wasn't there (and he had predicted that it wouldn't be matted because of what I had told him what I observed of flows.) We did clean it off anyway, but he thinks the problem is in the air flow restriction. Keep in mind that since summer I've tightened/sealed the system and cabinet a lot, so more flow will actually move past the coil than before--I expect that alone to make a measurable difference this year (it already has this winter.)

He figures the low cost short term option is to replace the evaporator coil with a properly sized one (and install a TXV). He says this is really only viable for 2009, because of the end of new R-22 equipment manufacture on Jan. 1, 2010. That's not necessarily what he recommends, just a "make the old system work as best it can" option.

He also noticed the catch basin was plastic/resin and showed some signs of warping from overheat, and tried not to touch it as he suspected it would crack if he did. (There was also about 1/8-1/4" wide gap on our end, a bypass stream around the coils. By my estimate that works out to about 3% of the total flow area, and at a fraction of the DP it might be 10% of the capacity of the coil, lovely.)

The blower is a three speed 1 hp. The old board is configured for high for the fan setting and the AC, but for medium (1/2 hp) for the furnace. I'm going to measure the blower draw during the next cold spell to verify. It's too bad that I can't set the fan to 1/2 hp (medium) during the summer so that I could get the circulation I need without running the AC as much. Afterall, with constant fan operation I don't need high velocity across the coil. The problem as he explained it is that if I tried that the old board would use the lower fan setting instead of the higher AC setting when the AC is on.

We also leveled the compressor and he cleaned the condenser coils. They looked pretty good from the outside and inside on a quick visual, but the space between the two rows of coils was clogged so that water couldn't get through. Eventually, he managed to get some water flow all the way around. He added that when he tore out old two-rows for salvage that he had just cleaned up, when he cut them open they were still full of junk stuck between the rows. His observation was that they only performed well the first few years. So while I have flow restriction in the air handler, I might also have been losing condensing capacity as well (and still will be, but to a lesser degree.) I guess I'll get a better idea this summer.

He's going to make a proposal for options on a complete matched system with variable speed. For this house, efficient blower operation can save a bundle while addressing stratification. He agreed with my plan for adding a return from the sub basement if I can figure out how to route it. He knows I'm in no hurry, but want some options for when this system has any serious failure, the savings/incentives look right, or when I get sick of trying to tweak the turkey.

 

On the bright side, his comments and information on the history of the industry/tech seem to confirm what I had observed: I was estimating that the system was operating more like an SEER 8 based on the energy consumption/home size, and degree cooling days. It was a pretty crude estimate, but took into account previous homes (in much hotter environments) that I've lived in as well as what the energy estimators claimed I should be using in the way of cooling for this region.

The system will most likely have to be replaced within the next five years anyway so it is more of a matter of "when" and "with what" than if. If I can just do the evaporator coil in the interim and make it work respectably for a few years, it might be worthwhile since it would debottleneck airflow in both heating and cooling to some degree. I'm already paying for the 1 hp/half hp blower operation and it chaps my butt to lose the airflow that should provide to a remediable bottleneck.

 

He's supposed to check on the part price but I believe he thought the part itself was in the ~$500 range (his cost.) It should be a drop-in to the existing Carrier box after removing the screwed-in blanking strips/brackets. It's more like a part swap with TXV added so it might not be too awful.

 

jayman,

I'm looking at $420 installed for the new coil and TXV. I'm planning to have this done if he gives the aged compressor a clean enough bill of health that it makes sense. (Hopefully not ending up like the vet visit to an old neighbor's ailing cow. She was down, Doc looked her over, then promptly sat down on her! When asked by an incredulous neighbor what he was doing, he replied, "She'll be dead in 30 minutes." And she was. He was a good vet, but his bedside manner left something to be desired.)

What do you know about Heil furnaces and air handlers? He's a Heil dealer and has quoted me a price on the VS 95 (which has the GE 2.3 ECM variable speed motor.) It's a two stage fire. Current old unit is an ~80% with 89,000 Btu/hr output, 110,000 input. This has some extra capacity at -5 F on a clear night with the wind howling--which is about the limit I've found in local weather records.

His original quote is for a 100,000 input (95,000 output for the 95%.) I asked and there is also the option for an 80,000 Btu/hr input (~75,000 Btu/hr output) in the same box/blower, it just deletes a single burner. I'm thinking this would be more comfortable and more efficient, even if it has to run continuously on high fire in a cold snap of the decade. But since it will have two stage fire I'm wondering if it is the best balance... (I doubt a prospective homebuyer would notice.) The cost difference is only about $100 so it comes down to comfort, efficiency, and "will it really have enough capacity?"

With the 30% Federal incentive, plus the local gas supplier's incentive, I can do the lot for ~$2,000. This will be sealed direct vent as well. Doing so will permit me to tighten the utility room, not a big deal, just an infiltration point that I've been wanting to address.

 

Update on the front loading washer: No problems so far. It has run well without any mildew problems or vibration issues. Sold the old top loading washer for $90 during a garage sale, haven't yet sold the dryer (didn't get much traffic during the garage sale, will try again this fall.)

The washer is saving about 10,600 gallons/year in water. I recently discovered that the sewer rate is not fixed on citywide average as my statement indicated for the first year, but is instead updated based on winter use. Since the sewer cost is $4.29/kgal, there is an extra $45/year in savings I had not been banking on...unfortunately it won't start until next spring, because my current rate setting period preceded the washer.

I estimate the total savings of the washer/dryer change out at $172/year based on utilities alone. Of that the washer is $158/year. (That doesn't include reduced wear and tear on clothing.) The washer will payout in 3 years and 10 months. That's not bad for replacing a functioning machine. If I had been deciding between a top loader and front loader to replace a dead machine the payout on the incremental cost difference would be about 1-2 years.