yaplej Posted July 5, 2017 Posted July 5, 2017 Hi all, So I want to see how much energy I am using just for my two HVAC units without investing in a full Brultech system just yet. I was thinking that maybe getting two Aeon DSB09104 units and putting one on each HVAC circuit instead of on the house mains. It seems like that should work. https://www.buydig.com/shop/product.aspx?sku=AEONDSB09104 My whole reason is to figure out if its worth replacing the windows in our house or just leaving them as is. Is there anything else that might be cheaper or work better?
stusviews Posted July 6, 2017 Posted July 6, 2017 How will that tell you if you should replace the windows? BTW, replacing leaky windows (and exterior doors) will save energy. That's what you need to analyze.
yaplej Posted July 6, 2017 Author Posted July 6, 2017 Exactly. I need to monitor my current HVAC energy usage. I can get the total from my bill so I only need to monitor the HVAC units and this looked like a cheap short-term solution.
larryllix Posted July 6, 2017 Posted July 6, 2017 While I wonder the same as Stu above, will the small amounts of energy saved ever pay for the Brultech equipment over the rest of your lifetime, or expected live in that house time? Comfort and/or a cool gadget and/or taking one for the environment, i can understand but there are much more economical ways to save energy/money. Without a direct connection to the wiring these things are just approximations of your power rate (They called it "wattage" repeatedly) and energy. Don't expect much accuracy, especially on a motor operated appliance.
stusviews Posted July 6, 2017 Posted July 6, 2017 Suppose you measure the energy usage. Suppose further that the reading are fairly accurate. How does that tell you that the windows are the cause of the high energy usage and not something else?
apostolakisl Posted July 6, 2017 Posted July 6, 2017 I monitor hvac usage at the church using ioguys isylogger program and programs in isy that set variables. Here is an example of the temp and humidity as read off of one thermostat in a building that has 5 total units (the other 4 units temp/humidity parallel this one so I omitted from graphs). You can see the 5 units running on the bottom of the graph and temp/humidity at the top. All 5 units condition the same room, so that is why I put this all on one graph.
yaplej Posted July 6, 2017 Author Posted July 6, 2017 The DSB09104 is a direct clamp type monitor so it should be pretty accurate and for only $20 its not near the cost of the Brultech. Im just interested in seeing if the majority of our electrical usage is HVAC because our windows are single pane glass and we live in Florida where its pretty warm Im sure that most of the problem is the windows. I would be totally fine being proven wrong and find that the majority of our energy use is elsewhere.
apostolakisl Posted July 6, 2017 Posted July 6, 2017 The DSB09104 is a direct clamp type monitor so it should be pretty accurate and for only $20 its not near the cost of the Brultech. Im just interested in seeing if the majority of our electrical usage is HVAC because our windows are single pane glass and we live in Florida where its pretty warm Im sure that most of the problem is the windows. I would be totally fine being proven wrong and find that the majority of our energy use is elsewhere. Ummm, your AC in Florida is going to be your primary electric use no matter what. You could have a super insulated building with 21 SEER AC and it would still be number 1 by a lot. I am sure you could cut your AC electric consumption in half and it would still be number 1. The question is not if it is the highest use item, but rather, if it could the highest use by less. And you are not going to answer this question the way you are going about it. First thing, look at your SEER. If you are running builder grade SEER 12 or 14 units, you would cut your electric bill by a lot going to a 19 SEER unit right off. If you have builder grade windows, your likely loosing a lot of BTU's that way too. You would need to know the windows ratings and compare to what you would like to replace with. Again, this will tell you BTU difference. You need to run a manual J on your house with your current window/insulation package and what it would be with new windows/insulation.
larryllix Posted July 6, 2017 Posted July 6, 2017 Window heat gain can be hard to calculate. Window R factors don't vary that much from worst to best but the radiant heat gain for AC on the sunny side can be brutal. Low E coatings and gas can help radiant heat gain a lot whereas here, In Canada not so much. It's all about conductive heat loss, mostly. We welcome heat gain during most of our year's seasons. Good windows, here, with Low E coatings and gas, cannot take most reflective films on the inside, due to trapped heat not having a place to escape either direction and many windows fracture from overheating when films are used against manufacture's warnings. The gas allows one wavelength of heat in, but not the reflected wavelength out. Apparently the radiant heat wavelength changes upon reflecting off home surfaces.
jtara92101 Posted July 6, 2017 Posted July 6, 2017 Your local utility or some local governmental or third-party agency probably has a home energy audit program. They are usually free or low-cost. Use it. The whole point is to determine the most cost-effective steps you can take to save energy and money. They can tell you what the most effective steps are just by inspecting your home and looking at your energy bills. Here's a couple of starting points: https://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_audits https://www.energystar.gov/campaign/home?s=mega FWIW, I helped write a series of apps (for Center for Energy and Environment in Minnesota - but apps shared with other agencies) for collecting energy audit data for both homes and commercial buildings for these types of programs. (The reason for 6 apps - every agency has their own ideas on what data should be collected and how to interpret it!) The data collected in WAY comprehensive. Data typically goes off to servers for analysis/scoring. They will typically give specific recommendations with costs and benefit analysis.
paulbates Posted July 6, 2017 Posted July 6, 2017 My thought on the reading the power is, what reading from it will you get that tells you "its the windows"? The issue with measuring power alone is that "a day is not a day". There is a measure of "heating degree days", because HVAC runtime - and therefor power usage, is affected by how hot/cold it is outside. Its hard to baseline what you are comparing day to day. A window replacement project is typically 5 digits, and if you already suspect the windows, you probably have reasons. The direct way to solve this is with a blower door test... An energy consultant installs a fan and monitor in an entry door and runs it for a while and the connected device can tell you how leaky the whole house is by how many times per hour your fully cycles its volume in air. The consultant also walked around with IR scanner and took images to prove his suspicions. A lot of it was also caulking specific areas that the IR camera showed. We could have benefited from windows.. but that would have turned a $4k project into a +$14k project. Windows would not have been practical for us. The biggest items found for us were the attic insulation and foaming the rim joists. It turns out that our power company offers rebates for the work if you have a certified assessment that includes the blower door test. An alternative, depending on your thermostats capabilities, you can have ISY programs tell you how many cycles per day and how much run time. I was able to use this around the insulation work we had done before and after. It was zero cost, just a little effort to program This was the "before" image, the after was less than half for the "South" unit which services the older part of the house. Paul
yaplej Posted July 6, 2017 Author Posted July 6, 2017 I checked my HVAC units and they are SEER 12. I also found our local utility offers energy audits for free. Ill be giving them a call to schedule one.
larryllix Posted July 6, 2017 Posted July 6, 2017 In Ontario, they forced us to install SEER 13 units over the last standard SEER 10 requirement. Higher than SEER 10 here would never break even for ROI in most people's lifetimes here. The exhobitant difference in cost and double-triple the size compressor unit, vs our two weeks of intensive usage plus a few months or light usage just doesn't make any sense. This is different situation in Florida and other longer cooling season locations.
apostolakisl Posted July 6, 2017 Posted July 6, 2017 I checked my HVAC units and they are SEER 12. I also found our local utility offers energy audits for free. Ill be giving them a call to schedule one. If you have SEER 12 I'm guessing they are at least 10 years old. There is a good chance that it isn't functioning at SEER 12 as well if anything isn't functioning at peak. The easiest way to lower your energy bill would be to replace your hvac with a SEER 19 or higher unit. The cost of course depends on how many units and how many tons. If you do an energy audit, you might find that you have more tons than you actually need. It is common practice to over-size units which costs more for the upfront and more to operate. You can pretty well tell how much your AC is costing you by multiplying your lowest electric bill by 12 and then subtracting that from your actual 12 months of electricity cost. Going from SEER 12 to 19 will cut that by close to half assuming your SEER 12 isn't functioning at peak and/or is oversized. This assumes that your lowest electric bill was during like March when you didn't run heat or AC at all. If you have electric heat, that is a consideration and if it is resistance heat . . .wow, that is very expensive. Heat pumps are way cheaper to run at reasonable winter outdoor temps like Fl would typically have. AC replacement will likely cost much less than new windows and likely save as much money based on starting off at SEER 12. Current code requires SEER 14 in most places. I suppose those canucks so rarely use AC that it doesn't make a hill of beans difference what SEER your AC is.
larryllix Posted July 6, 2017 Posted July 6, 2017 A new gadget was added in my last A/C installation to increase the SEER rating. IIRC: It is an inline thermally sensitive device, that restricts the coolant flow until the temperature drops. It gets the compressor pressure up faster, increasing the efficiency of a starting system compressor.
apostolakisl Posted July 7, 2017 Posted July 7, 2017 A new gadget was added in my last A/C installation to increase the SEER rating. IIRC: It is an inline thermally sensitive device, that restricts the coolant flow until the temperature drops. It gets the compressor pressure up faster, increasing the efficiency of a starting system compressor. That is what a thermal expansion valve does. (TXV for short). Been around for decades. I am pretty sure that 100% of hvac systems have one installed, at least for a long time.
stusviews Posted July 7, 2017 Posted July 7, 2017 We have a thermal expansion valve in our more than 17 year old Carrier HVAC. The valve was replaced about 2 years ago.
larryllix Posted July 7, 2017 Posted July 7, 2017 I guess we never worried about better than SEER 10 that much before. Maybe I never looked before? People here never worried about a few bucks saved per year more to pay $5K for an A/C units when a SEER 10 unit was about $1K. Then the greenies bully the government and things change.
apostolakisl Posted July 7, 2017 Posted July 7, 2017 I guess we never worried about better than SEER 10 that much before. Maybe I never looked before? People here never worried about a few bucks saved per year more to pay $5K for an A/C units when a SEER 10 unit was about $1K. Then the greenies bully the government and things change. Well, I'm no fan of gov't mandates. But if you live somewhere where the AC runs for 3 weeks per year, it is pointless to spend the money on high SEER. But when you live somewhere that AC runs 9 months per year, and where you don't have nat gas so you have to heat with either propane or electricity, it makes very good sense to spend the extra money, not only to go with the gov't mandated 14 SEER, but to go beyond. I have a 19 SEER unit in my house. That was 10 years ago, today, I would go with 21 SEER.
larryllix Posted July 7, 2017 Posted July 7, 2017 Well, I'm no fan of gov't mandates. But if you live somewhere where the AC runs for 3 weeks per year, it is pointless to spend the money on high SEER. But when you live somewhere that AC runs 9 months per year, and where you don't have nat gas so you have to heat with either propane or electricity, it makes very good sense to spend the extra money, not only to go with the gov't mandated 14 SEER, but to go beyond. I have a 19 SEER unit in my house. That was 10 years ago, today, I would go with 21 SEER. Yeah for sure. Many of my neighbours, shaken up by the rising energy costs and TOU metering introduced a few years back, won't ever turn on their A/C. In a few days we will have 95F and fog (85-98% RH) in the area. You need another place to go between car A/C and stores to restore your electrolyte loss muscle cramping. Pass the bi-carbs! Luckily it only lasts a month or so usually.
abuttino Posted July 11, 2017 Posted July 11, 2017 If you have a nest, I have a lot of different ways to monitor your ac usage. Check my Nest/ISY/Tasker thread Sent from my Pixel XL using Tapatalk
abuttino Posted July 11, 2017 Posted July 11, 2017 Look at this too: http://www.tinozplace.com/nestchart.png Sent from my Pixel XL using Tapatalk
larryllix Posted July 11, 2017 Posted July 11, 2017 Look at this too: http://www.tinozplace.com/nestchart.png Sent from my Pixel XL using Tapatalk Looks like Las Vegas. You have very dry air, except when it rained on the night of July 7th.
larryllix Posted July 12, 2017 Posted July 12, 2017 Phoenix Sent from my Pixel XL using Tapatalk Can I ask you the size of your HVAC house area and the size of your A/C compressor system, just for comparison? I have 1710 sq. ft. and a 2 ton compressor (~24,000 BTU/h) and our humidity ranges from 50% = dry day to typically about 70% on a normal summer day. Temperatures ranges 60F - 75F at nights to 72F - 97F during the day. Peaks stated are extremes. MY HVAC runs about 40 - 100% of the time to maintain inside comfort = 73F @ 45% RH. HRV increases energy usage dramatically to reduce new moisture.
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