Alternative Energy thread

first guess. Nurse. almost 4 feet long now.

 

That is a fair size home. WRT A/C performance, I think a lot of systems are poorly designed and then poorly installed. It goes downhill from there.

First of all, what are line boosters? If you mean those supplemental electric fans you put into round 5-6 inch ductwork due to poor airflow, save your money.

They're not worth it, they make little if any difference. You also have to figure out how to make them turn on with the system fan, involving a lot of understanding of relay's and wiring.

If you have a split system in the attic, are the main trunks and supply ducts sealed and insulated? As an attic has the potential for enormous heat buildup, not only does the A/C have to cool the interior, it also has to make up for the heat gain in the attic.

Poorly sealed ductwork alone can cut +75% from your potential airflow. Of course, it's a messy and potentially dangerous job to crawl around in the attic trying to seal the ductwork.

If your ductwork is in the floor, that is the absolute worst place for cooling performance. Up here, we require ducts in the floor due to our priority for heating performance: ceiling ductwork works poorly at heating.

When I had my new hobby farm home built 2 years ago, I paid particular attention to the ductwork. It was disturbing the heating contractor wanted nothing to do with sealing and insulating the ducts "why bother, it'll work?"

Since my floors have I-Joists, the way they slapped the sheetmetal on to create cold air return plenums meant a half-inch airgap on either side, due to the I-Joist. So I spent a lot of time with "real" aluminum duct tape and Tuck Tape to seal every obvious crack and seam on the return plenum.

On the supply trunk and supply ducts, not only did I seal the cracks and seams with aluminum duct tape, I also put R-12 insulation on them. The difference before/after is startling: before I barely had any airflow out the furthest registers at high speed; after, the airflow at medium speed is quite strong. High speed is uncomfortable, too much airflow!

Since my HVAC is a Bryant with their "smart" Evolution control network, it determines variable speed fan settings, heating fire rate, and cooling low/hi Scroll condenser operation, based not only on interior temp rise/fall but also on outdoor thermometer reading. This creates a PID (Proportional deadband, Integral, and Derivative) control loop.

In summer I only turn on the A/C when I arrive. It will stage to high fan speed for about 10 mins, then ramp to low as the interior temp reaches setpoint. The scroll compressor then runs on low speed. In winter, I've only heard high fire and high fan speed a couple of times at -40 with strong windchills.

My utility bills speak for themselves. To date my highest gas bill has been this January at $168, comparable homes +$280. My highest utility bill has been $90 every two months, comparable homes have +$90 every month. I use so little electricity Manitoba Hydro only bills me every two months.

I think the remote split ductless systems for cooling are far more energy efficient, as you're not dealing with the high energy loss associated with ductwork. The evaporator is ceiling mounted to quickly and efficiently cool, as hot air naturally rises. Since the unit is directly combined with the fan, no losses from ductwork at all:

http://www.mrslim.com

There are many DOE resources that explain the critical importance of sealing and insulating ductwork. Scary to think that 40-70% of the energy used to run your heating or cooling system is *wasted* :

http://ducts.lbl.gov

Given your climate, you should be able to replace the exterior security lights and entry lights with Compact Florescent or High Pressure Sodium. Up here, you can't use Compact Florescent lamps for exterior security lighting as they usually stop working at 0 F or colder. So at -40 it's SOL, unless you like the yellow glare from HP sodium lamps.

I suggest you find a reputable (Good luck!) energy consultant to determine where your greatest savings may be achieved.

Doesn't the State offer any resources to help you there?

 

ducts are in the floor. AC unit and heating are both on 1 side of the house.. unfortunetly.. the smaller side of the house. So.. by the time this air reaches the large side of the house it's poor output and usualy not as hot or cold as the air on the other side of the house. Insulationa and duct work is not a problem. i did construction as a living. ironic, my father is a general contractor. not the brightest in the bunch through dont' tell him that. lol.

my idea for the fan would help take air from the other side of the pipes. air is supplied.. but the long distance just kills the pressure. i put a fan ove the vent and semi sealed it. it made a huge difference. a fan in the duct is a small investment for more pressure. the ducts are taped. it's all petty sealed. we check it ever year for new leaks.

 

What?!? You live in San Jose and the registers are in the FLOOR?!? Is that even *legal* there?? Who dreamed up the HVAC for that house??

:Wth:

I suppose heating performance would be ok, but it's not like you have a huge priority for heating performance there. I know the area well, my Aunt and Uncle live in Santa Rosa. BTW I love your area, cool people and nice scenery!

Especially if you have tall ceilings - anything over 10ft in my book - forget about any sort of reasonable cooling performance with floor registers. You could stick a 6 ton unit in, and it wouldn't help.

As the ducts are in the basement -or God help you crawlspace - it still wouldn't hurt to insulate them. As far as boosting the airflow, with air distribution that fubar'd I suppose you do need the duct booster.

You will have to figure out how the auxiliary A/C relay (C1 and C2) is wired off your thermostat. Eg is it staged or just single stage? You will then need to wire up a relay box to turn on the duct booster only when the furnace fan is on.

This still will not be the ideal situation though. Your primary HVAC usage is for cooling, and there is *no way* floor registers will work for that in your climate.

I would *not* want your electricity bills. In Ontario, with the mess left behind by Ontario Hydro, if you used 4,500 KWh a month it would cost around $500. Even here in Manitoba it would cost around $280. No thanks.

I would visit the Mitsubishi Electric site I posted above for information on their "Mr. Slim" ductless A/C. Since the cooling evaporator is mounted up against the ceiling, it's the most efficient as it's drawing in the hot ceiling air. You might be able to keep that house very comfy with a 3 ton or under.

I have a huge assortment of HVAC planning material if you need more advice. In the meantime, we won't give your Pop any more grief. Poor fellow.

 

yep.. in the floor.. and insulated already.. well.. crawl space for most of it.

as for the leads from the thermostat.. not hard. i installed it. i would have to remember the wiring though *shrug* o well.

i need to check out your ductless ac system you talked about. didn't view it.

I live in south San Jose. it's actualy New Almaden. If you know Calero resivor or a restaurant called the La' Faret... either ring a bell? i live in that area. Basically.. Almaden Expressway till it ends... but about 2 miles past that point. Very nice area out here. We live right next to the Quicksilver Park system. maybe you know that area... *shrug*

I'm gonna check out a/c system *runs outside*

uhh.. it's not very efficient. it's a huge system. 4 feet by 4 feet.. about 3 feet tall... it's better at heating then cooling... but that's just what the energy guide on it says.. but we didn't set it up for heating. lol. that would be expensive.

as for power usage.. we pay more than that. but yeah... it sucks. this is why i like the investment of solar. cost more up front.. but less in the long run. energy usage won't really go up.. but cost will. over the next 30 years, cost will be a lot higher than now, most likely.

 

Jayman-
Once again, you are giving pretty good advice and showing yourself to be well informed. These are complex issues and are difficult to address adequately in this forum, but you are doing it fairly well. I would like to comment on a couple of issues.

I wouldn't recommend using tape for sealing of ductwork. On metal ductwork, mastic is the only way to go. It must be worked into all the seams and joints, not just painted on. When you externally wrap insulation around ductwork, it is very important to maintain a continuous and undamaged vapor barrier on the outside of the insulation. The foil paper that you see on ductwork is intended as a vapor barrier and it is only here that foil tape is appropriate. When this paper is torn, moisture will be drawn in during the cooling season. The insulation will become wet and eventually the strap hangers supporting the duct will come loose from corrosion at the screws that support them. Good HVAC work is hard to find.

One of the best things you can do for yourself is to make sure that all ductwork is located within the conditioned space. This one thing will cure alot of problems and save alot of energy.

I don't type as well as you so I will stop here for now. I enjoy reading your posts.

 

Ray:

Sorry about that you are absolutely correct. Once again my fingers went far ahead of my brain and I assumed a lot of that into my post. FWIW the DOE link on duct leakage and performance I provided does cover that in good detail.

I think the aluminum foil tape is ok for tight seams, but right for any obvious gaps you must build up the gap and use mastic. Some folks have used regular silicone sealant but I'm not sure that is suitable for HVAC.

The insulation I used is that HVAC stuff so it already has the vapor barrier in it. Again, I should have mentioned that. I suppose regular fiberglass is better than nothing, but it will do nothing to prevent condensation and air flow.

Personally, if it was up to me, I'd ban sheet metal ductwork and require fiberglass ducts with the insulation already applied. That seems a lot more goof-proof.

The biggest problem and PITA I have with HVAC contractors in general is that - as a group - they are a remarkably uninformed and stubborn bunch. A lot of them still oversize a system just to "make it work" instead of doing the brain work ahead of time to properly design, install, and commission the system.

For example: up here the HVAC contractors will slap sheetmetal over the I-Joists to make a cold air return plenum. They don't even give a rat's a** about the automatic 1/2 inch airgap on either side of the I-Joist.

So gee, wonder why the airflow out the register is nowhere near what it should be??

This is a lot more important as homes become tighter, thanks to 2x6 walls, Tyvec house wrap, and good windows. Especially with an ICF wall, the house is just about airtight. So there are *huge* IAQ (Indoor Air Quality) issues here.

The "obvious" solution is to install an HRV (Heat Recovery Ventilator). The HRV is even more sensitive to duct design and installation than the HVAC is. I've been in many homes where the contractor just used the regular 2x4 interior partition wall to make a plenum for the HRV.

So the HRV is sucking air not only from the vent (Bathroom, kitchen, whatever) it's also sucking dusty air and sawdust and shavings from the 2x4 closed partition between two sheets of gyproc. So with all those air leaks, it will barely draw at all from the place it's supposed to.

Combined with ducting that isn't sealed off, and the HRV can be run on its highest fan speed with barely any draw from the vents. The standard foam filters shipped with the HRV will quickly plug with all the crap in the ducts, and the finer dust goes right through to plug up the HRV core.

Ironically, around here an HRV may make IAQ worse. Once you get buildup on the HRV core, you get mold growing. Since most of the HVAC crackpots around here put the vent hoods the minimum 12 inches above finished grade - hard to believe in this climate that's all that's required - , in hot summer they suck up all the dust and dirt. In winter they're blocked by snow and ice.

So this is a very complex issue. I've found myself almost constantly in a huge pis**** contest with some HVAC "expert" who refuses to change the way he has installed systems over the past 25 years.

Good HVAC work isn't hard to find - it's *impossible* to find. So everytime I go through the process of building a new home, I cringe. Because I have to go through this bulls*** all over again.

 

My Aunt and Uncle have driven me through that area several times. It's very nice there, wish I lived in your area instead of this frozen wasteland. My Uncle had a nice pad near the marina (Alameda?? You could see part of the Golden Gate and that old Navy base) before he married my Aunt.

He sold it in '86 and still groans about that, it would now be a multi-million property. Better invest in the Crystal Ball.

Back to your A/C problems: see if your State offers an Energy Audit. This is usually free or very low cost and will pinpoint where most of your energy use is. Given your bills and difficulty in tracking down the suspect contributor, it will be cheaper than guessing.

Given the climate, I would still think A/C is your biggest single energy use in that house. I don't know how high your ceilings are, or whether the house is single story or split/bilevel etc, but just the fact the registers are in the floor you are doomed with those high bills.

In a hot climate, you just can't stick registers in the floor and expect good cooling performance. Much like up here you can't stick the registers in the ceiling and expect to keep the floor warm.

Please check out the URL to the Mitsubishi Electric of America ductless A/C system. At the very least, you will have proper cooling performance with the evaporator mounted against the highest part of the ceiling. This will allow you to raise the cooling setpoint and dramatically reduce your cooling bills. You should also be able to run a much smaller system than you currently have (5 ton currently? 6 ton??)

As far as lighting, my Aunt and Uncle have had great success with compact florescent and also the new LED lights. The LED's are best suited for lights that must stay on for long periods eg security lights. When you compare 5 watts to 60 watts, the savings add up quickly.

 

I've looked into LED Lighting a while ago. I wanted to wire up and install them in my house. The spectrum is a little odd though for certain lighting. Maybe an uplighting would work with it? hmm.. I know the High Output LEDs would work.. but a huge strand is kinda complicated.. well.. time consuming and a lot of soldering.

 

Jayman-
Fiberglass ducting(duct board) is one of the worst things you can use in your home. We always find mold growing inside it. It can't be cleaned. When it ages, it breaks down and fibers become airborne. From an IAQ standpoint, fiberglass ducting is an environmental disaster reminescent of asbestos. It's only redeeming value is that the fibers are large enough to be irritating to your lungs. Oh, and it has saved huge amounts of energy on the cheap. There are coated versions that encapsulate the fibers but the savings compared to metal are not substantial.

 

i think i found my solution. i'll buy a stand alone system for my room. my room is detached from the house.. but if i have my own battery system and solar panals.. i could be an example for this area. plus.. no one could complain about using too much electricity.. except for me.

 

Ray:

I didn't know that. All the press I've read made it sound like the best thing since indoor plumbing. I was all set to use it in my next house too.

What you just described makes perfect sense. So it looks like regular sheetmetal with a lot of elbow grease on my part to make sure it's sealed and insulated.

I *knew* it was just too good to be true! :cussing:

 

You mean a standalone ductless A/C? I suppose that makes sense. If your home has very high ceilings or multi-level I wouldn't bother anymore with the floor registers. Take a serious look at the ductless system.

LED lighting is available in Edison base:

http://www.ledtronics.com

 

Taken from the website that Jayman provided.

"Today, for general lighting (e.g., living areas, factory floors) applications an incandescent bulb generates more visible light-per-watt than an equivalent LED, making an incandescent better suited for this type of job. However, it's in color-specific and power-critical applications (e.g., third brake lights, display panels, industrial controls and traffic signals) that energy-efficient LEDs really outshine incandescents. "

I sure am ready for a good alternative to incandescent but there isn't one I can live with yet for general purposes. Dimmers are good though.

 

the only bad thing about dimmers is that the energy gets pulled. extra just get waisted in the dimmer switch. i hear they make dimmer that actualy draw less power as you dim. most trade the extra non dimmed power off as heat. if you hook several hundred watts on to a dimmer, it heats up. normal switches don't.

dimmable compact florescents cost a lot *shrug*.. i just want a huge 12 pack for a good price.. too much to ask for?

 

Actually if you dim to 25%, you only use 50% of the energy so not all goes to heat. If you dim by 10%, you will double the bulb life. Here is a quote from the Lutron website.

"Dimmer Switches Increase Energy Conservation:
A dimmer switch actually turns a light on and off rapidly - approximately 120 times a second. However, your eyes see a steady dim level of light. The lower the light level, the greater amount of time the light stays in the OFF position thereby using less electricity. A light bulb set on a lower light level also produces less heat, increasing light bulb life. Tests have shown that dimming an incandescent light bulb 10 percent saves 10 percent in electricity usage making an incandescent bulb last twice as long. Dimming a light 75 percent saves 60 percent electricity and the bulb lasts more than 20 times as long."

Here is a link to their website:
http://www.lighting-fixtures-ceiling-fans....er_switches.htm

Yes some energy goes to heat but only a portion. Good quality dimmers are more efficient than cheap ones. As always: Don't shop at Walmart. You can't afford the money you will save.

In the summer it is important to remember the sensible load on the HVAC system generated by lighting. In the winter, lighting reduces your heating load.

 

That's why I mentioned there are specific uses, such as security lighting where the lamp must be on for long periods, where LED long-life lamps make the most sense. That’s why you see them on Exit signs and traffic signal lights.

At my hobby farm, I use a 5 watt LED for the porch entrance. Since it's very dark in there even in daytime, I just leave it on 24x7. It provides just enough light so I don't have to fumble for the key. Unlike CF bulbs an LED works at -40.

I also use the LED's as night lighting in my hallways, bathrooms, and basement steps. Total, I have around 40 watts and have a safer house. The equivalent in CF would be around 96 watts.

What I like about LED is that they should last 100,000 hours. They are starting to be used in more industrial applications, but it's hard to design a lamp to provide equivalent lumen output to a short-lived incandescent. However research is being done and a lot of folks are optimistic.

For large industrial use the focus has shifted from High Pressure Sodium to Induction lamps. The Induction lamp is a more natural daylight color and will also last 100,000 hours.

http://www.nam.lighting.philips.com/us

http://www.qlinduction.com

For the outside yard security lights, I have a Low Pressure Sodium 18 watt lamp above the porch entry door and another one above the detached garage entry door. For the old barn/shop, I have a Low Pressure Sodium 55 watt. A lot of folks find the deep orange/yellow glow rather sickly, and they can take 10 minutes to warm up to reach full lumen output.

Incandescent lighting is remarkably inefficient and I would not recommend its use in an commercial, industrial, or large residential application. I will admit I use a 60 watt incandescent for reading, but that's it.

Most large residential, commercial, and industrial settings are well served by florescent lamps with electronic ballasts. The electronic ballasts allow dimming, and are much more energy efficient than traditional magnetic ballasts.

As far as dimmers, you really want to invest in the commercial electronic dimmers. Most dimmers work as V8 mentioned, they use a resistor or a dumb electronic circuit to lower voltage, creating heat.