SketchUp + Energy Performance, Part 6

(part 1)
(part 2)
(part 3)
(part 4)
(part 5)

OpenStudio Plugin for SketchUp, another brick in the EnergyPlus wall.

SketchUp + Energy Performance, part 5

(part 1)
(part 2)
(part 3)
(part 4)

Here's a short entry about Energy Analysis Plugins for SketchUp.

SketchUp + Energy Performance, part 4

(part 1)
(part 2)
(part 3)

I think I'm going to stop referring to HVAC-Calc, lest there be any confusion...

Anyway, the saga continues - and here's the last installment: See your building's energy performance - and note, it's free.




Let the fun begin.

So what is a heat load calculation?

The answer is here (part of the homeowner's FAQ).

SketchUp + HVAC-CALC, part 3

(part 1)
(part 2)

Now, Official Google SketchUp blog reports that the beta version is available for download.

Hurry before they change their mind.

SketchUp + HVAC-CALC, part 2

You've read it here first. Now someone closer to the subject area implemented it: Energy Analysis Tool for SketchUp.

Told you.

SketchUp + HVAC-Calc = ?

Loosely quoted, "Good companies have many great ideas. Great companies know which great ideas to discard".

Alas, I will not have time to implement this, nor ways to approach the Big Guys to make this happen, but I wonder - am I the only one that sees an obvious symbiosis of SketchUp and HVAC-Calc?

Granted, it's not a five minute project, but all the necessary components are already there - and it won't be that difficult (especially for big guys like Google) to implement a real-time heat loss and gain recalculation as one works on the model of the house...

One of the most important features of SketchUp is that it, being a Google application, evolves fast. Plugins are there, too. It would be really interesting to see where it goes - SketckUp Blog is a nice place to keep an eye on it.

More on SketchUp later - it might have many obvious and not so obvious ramifications on the ways home automation, HVAC and general improvements are done. For example, the most obvious side effect of one creating a house model is that all the hidden spaces you've never thought about become obvious, and the task of routing your cable system becomes significantly less intimidating.

to be continued...

A/C Can't Keep Up?

Been there...

First of all, if that's the case (and not the phenomenons described in Thermostat Wars), it means that something is pretty much busted in your HVAC system.

Not necessarily the unit itself - ducts may leak, filter may be dirty (how many years ago did you change it last time?), you may have cut the trees on the southern side that provided you with shade and so on and so forth. Best bet would be to assess the overall system status - but that's going to cost you.

Next best assumption is - you don't have money not only to fix something if it is broken (1), but even to assess the status. Or, for some reason, this is not practical (say, the assessment, fix and/or upgrade is planned and budgeted, but the right time hasn't come yet). Well, this is not a nice situation to find yourself in, but not all hope is lost.

All the things below are pretty trivial in retrospect, but sometimes not obvious upfront, so I'm going to lay them out anyway.

First of all, set the thermostat to a lower temperature early in the morning and leave it there. Your house will store some energy and will help your A/C fight with the sun. You must realize this will somewhat increase your electric bill - but not much.

You probably heard that you can't run evaporative (a.k.a. swamp) cooler together with your other (known as refrigerating) A/C - the swamp cooler will be busy injecting humidity into the air, whereas refrigerating A/C will be busy removing it from there - thus adding $$$ to your electric bills and doing little else.

Also, be ready that the house will be significantly more difficult to cool some time after you stop using evaporative cooler - all that humidity it pumped in is still there, contained in the air, clothes, carpets, stuffed furniture and building frame.

Close all the blinds and shutters you have. If some of your windows don't have them, go buy some - they're relatively cheap and will significantly improve the insulation - not only they block the sun radiation, but also introduce insulating air pocket when closed.

Go get some insulation sheets from your favorite home supply store and stuff them between the shutters and windows - bad windows may contribute as high as a quarter of total heat load to the house.

Along the same lines, if you're planning to improve the house, don't go cheap on windows - get dual or triple pane tinted windows - and do your homework on selection. Makes the world of a difference - our upstairs bedroom on the south side of the house with good windows installed was significantly cooler than north facing rooms with old, single pane aluminum frame windows.

Make sure your ceiling fans work for you, not against you.

Well, that's just about it for starters...

In addition, there's a nice article about Tricks to Keep Your House Cool This Summer (except for the section about fans, which I disagree with) - and make sure you read the comments. Have to apply a good sanity filter to those, though...

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(1) Having home warranty is relatively painless way of making sure this never happens; will cost you anywhere up from $250 a year, depending on the features - whether you have a pool, etc. - but it opens another can of worms altogether.

Honey, there are gremlins in the house!

Like the saying goes, "Flying is the Second Greatest Thrill Known To Man, the First is Landing".

The most thrilling part of getting into a new house is the first night. Or any night, for that matter, until the dust settles. It's the time when you find out with excitement that the people that sold you the house forgot to mention that the neighbor behind the southern fence likes to play his electric guitar off key at 5AM, or that the guys across the street get their truck that is older than me out of the garage and start fiddling with the engine and revving it at about 11PM... You get the picture.

Then, deeper into the night, you start hearing noises. The one I'm talking about drove me nuts for several months until I figured out what it was. It's quite rare (so far), because the only HVAC units affected by it are the ones that are slowly ramping up and down.

I'm taking about loud bangs in more or less rapid succession, seemingly all across the house. Gremlins.

Hindsight is always 20/20, and now that all the facts are laid out before you it is quite simple to see what it is: it's the flat tin panels that comprise the ducts flipping back and forth when the pressure changes, all of them at different times. What makes it fun is that the sound pattern changes as the building ages - panels that used to be well insulated and thus somehow dampened are not anymore because of the insulation breakdown, and the more time passes, the more pronounced the phenomenon becomes.

It is also an indication of the fact that the pressure in the ducts is quite high, probably way above what it should be.

The best part? There's probably nothing you can do without significant amount of money or elbow grease injections, so might as well get used to it.

Proper fix, though, assuming the pressure is within reason, is to apply sound dampening materials to the outside surface of the ducts. I guess the trick would be to find a material that sticks to the surface and doesn't let it bang, and at the same time won't break down for a long time.

There are also products called "acoustic duct liners", but knowing how widespread the problem of undersized ducts is, I would be extremely cautious stuffing anything alien into the ducts, unless you're absolutely sure the duct itself is grossly oversized.

Which returns us all the way back to the heat loss and gain (a.k.a. heat load) calculation, but that's a different story for a different time...