Anyone out there using eQuest, EnergyPlus, Sketchup in retrofit audits? If so how. I know these programs are great for design of new structures, so how can we use them for retrofit? After all these programs are developed by great Institutions and distributed FREE with a lot of people using them. Maybe we could get a standard program that we all could use in our field without it being expensive to purchase. Any thoughts?
The Home Energy Saver Pro tool is primarily for retrofit analysis, and is available to any and all users at zero cost.
We've done extensive accuracy assessment.
Working with most of the local and national energy programs, I have to use a number of different energy modeling programs. Seems each modeling program has a different set of problems. I always start with running my home as a baseline.
Zone 5, 2700 sqft, 4 people, big local builder, his first Energy Star 2.0 (I supervised/installed measures like air sealing and envelope measures, then brought in third party for qualification), R-19 walls, R-38 ceiling, R-10 unconditioned basement walls, casement windows, insulated ducts with some in attic and basement, 95% gas furnace, 15 SEER AC, HRV, gas tankless H2O, Energy Star and better appliances, most used lighting is CFL/LED. I have spread sheets for all utilities since home was built.
A while back I ran HESPro and again today checked inputs/output after seeing this post. I have several concerns:
Whole house- electric total kwh/yr about what I chart for past few years but NG is about twice what I used over past several years.
Heating - lists upgrades saving 31% on electric & 23% on NG (729 T/561T). Existing furnace unit is 95% and TOTAL NG averages 550 +/- per year. How do I upgrade - cut the system off 31% of the winter? That would save the 31% electrical, but what about NG? NG is calculated way high.
Cooling - yes, there are higher efficiency AC units out there but saving $34/year is not going to make replacement an option.
Hot water - Since there was no tankless option in the program (unless I put in tankless off a boiler which does not go with hot air furnace) I see this a a significant factor in the over estimation of NG use, but not as big a problem as heating. During summer (with no furnace running) my NG use runs 5-10 ccf/month which is lower than the after upgrades listing.
Large Appliances - Lists 20% improvement after upgrades. How is this possible since I have Energy Star and better?
Small Appliances - Lists over half of total electricity used in this area and shows no improvements/upgrades. How is this possible?
Lighting - Shows 93% possible improvement. I have replaced most all lighting that sees regular usage with CFL/LED. Even if I replaced every light with CFL/LED I could not get 91% improvement. Since the existing non CFL/LED lights are not used much, maybe 20-25% as much as the existing CFL/LED lighting and changing them out to more efficient bulbs saves about 80% of the energy they would have used gives me an estimated lighting savings of (20-25% of total use x 80% savings) 16-20 % over all savings on lighting. This is an area I am slowly replacing bulbs as better designs become available. Not all energy efficient bulbs work in all locations.
To summarize: All the energy software programs have problems. You cannot take all of any of the software program results as gospel. You need to apply some common sence in using their outputs. If you are required to use a specfic modeling software to report in an enery program, provide your client (home owner , builder, program director) with additional notes explaining the over/under stated outputs.
Clarification: I do not use HESPro on a regular basis as it is not the approved/required software for the programs I work with. I just like to undersand what options are out there and see if they offer a better solution than what I have seen to date.
Part way through that and thought I'd mention that I really enjoy your stuff, always something interesting to learn.
In our first data cohort, below, ten homes had
identical refrigerators, one of which used 50% (400 kWh/year) more energy than the
average of the others due to a door gasket had been torn upon installation. Errors in data
entry can also be important.
I, too, am always looking for the killer Retrofit software
Architectural Energy's REM/Design ?
Randy, this is a great question, so I'll give it a bump.
There is nothing like looking at the floor plan and your notes when building your (TREAT in my case) energy model, and next when designing improvement recommendations, and pricing them for cost benefit. I would love to abandon graph paper for this.
Anthony, not sure what you are saying. Is your home using 200t more than you expected? This hasn't always been the case? Since it appears the water heater is not the culprit, do you have modulating or single stage equipment? (95% is 95%, right? WRONG!! It indicates a label given in laboratory conditions. Some are total pieces of crap that could never deliver in varying loads and duct conditions seen in the real world, and others optimize output and efficiency by design - you may know this but many reading may not.) When was it last serviced?
Ted - "not sure what you are saying" ?
Maybe you just did a quick glance- it was a long post. You missed the point of the post - the software does not provide an accurate picture of an existing home. How can it provide reasonable upgrade information if it cannot baseline the house?
My house is not using "more than expected". The program is calculating far more energy use than I actually used over the past several years. The program computer run had real inputs into the program (I had it built, I supervised the airsealing, insulation and HVAC to meet/exceed Energy Star) and the program gives a baseline that grossly over states the energy usage (I have years of detailed energy usage). Then the program makes estimates of possible savings that are totally out of the realm of possibility.
To address your hot water comment - I have a NG fired, modulating tankless hot water heater. My comments pointed out the program does not give this as an entry choice. I then suggested maybe this was one of the reasons the program overstated my actual NG usage, followed by a statement that actual hot water use in months without actual NG furnace use was in the range of only 5-10 ccf per month - not a lot. Also this is much less than the program listed for usage "after improvement".
"95% is 95%, right? WRONG!!" - again read the post. What ever program (Remrate, Treat, BEOpt) you use, you have to plug in equipment efficiency numbers. This is Lennox number but with my combustion testing equipment I get close on reading. In any case, I plugged it into this program and out popped a usage of 38% more than my actual. You are going to use this for recommending a group of improvements which is only getting you down to where I already am? This is a problem with the program building the existing baseline.
Several areas the program came up with "savings after improvement" that are totally impossible to get. It all stems from garbage in, garbage out - if the program does not provide a proper foundation, the house will not stand for long.
I read your whole post, twice. It's just hard to read. Seems you wrote it as if you were reading it, not somebody who has no idea about your situation. I understand how that can happen as I do it a lot too.
Awesome that you see this glaring problem, I've been lobbying for change to this for over a year in NY where truing models has not been required (and as such, 95% don't even know what it means!). I suggested that if they didn't get accuracy tightened up, roll out of On-Bill would be a catastrophic failure (which I see as a huge, unnecessary tragedy).
Like manual J has a tendency to oversize, modeling software has a tendency to overestimate consumption. I suspect this is due to fudge factor in various places. Good software allows an additional step, called "true up" (which in actuality is truing down to actual consumption - which on average is about 35% too high!).
So yes, hard to have confidence in a program telling you what you will save, when that savings is more than your total spend! When I play with a tool that tells me I'm spending $7k and can save $3k, and I spend under $2500, all credibility is shot. These programs are like somebody connected millions of dots, except the last two.
ACCOUNTABILITY for promise should put extraordinary pressure on fixing this. I've been promoting my thoughts on how that could happen. Maybe you have some ideas?
Interesting discussion on SketchUp here: Google SketchUp for Home Energy Raters - Measurements Made Easy
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