Ok, the BBS has never let me down on bizarre questions. I have a stucko/plaster house (inside and outside) that I am trying to heat. It is poorly insulated (yes, i know, it needs to be insulated) My central heat sky rockets during the winter and it doesn't not keep my house reasonably warm. I looked into adding a 97% efficent infered gas heater in a couple of my rooms from the utility company. They strongly suggested I go about a different route because the plaster houses/ 97% efficent heaters combo creates heavy moisture buildup on the walls that literally leaves the walls dripping wet and causing mildew buildup. Venting gas heaters, cental heat and other types of structures (wood, sheetrock, ect) does not create this problem. They did not know why or provide a solution. I am considering going this round and getting a dehumidifier. Does anyone have any idea why this might happen?
Well, I'm not even sure what a stucko house is but... The reason that central units do not cause heavy mildew is because they circulate the air and they remove it from the home. That is why you will see the pipes coming from the roof with the gas fumes coming from it. If you are not going to insulate take into consideration many other factors as well. i.e. the doors, windows, carpet vs. hard floors. I'm no expert but I have taken a few courses in college. I just don't do it for a living so i'm kinda rusty...
There's quite a bit of moisture in natural gas. That's why many high end gas range manufacturers (like Viking) make "dual fuel" ranges. Gas for the cooktop; electric for the oven. Why? Although a bunch of moisture is pretty good for roasting meats, it's NOT good for baking. Moisture in the oven is like salt in soup. You can always add more (like with a drip pan filled with water), but you can't take it out. Anyway, non vented natural gas heaters put a BUNCH of moisture into the air. That's okay if you live up in the mountains or in the desert or somewhere where it's usually dry. I don't think it would be a good idea in Houston. You will end up with quite a bit of mildew problems.
Pole explained it very well. I didn't know natural gas had a lot of moisure. But why does it cause problems with plaster but not other types of material? Perhaps they absorb it? Would a dehumidifier work?
I'm not positive, but I would guess that this would defeat the purpose. Why? Because the moisture you would be taking out of the air is actually carrying around your heat. Cold, by definitition, is just the absence of heat. When you put something in a fridge, for instance, you are--by definition--not chilling it, but removing heat from it. When you use a ventless heater, it produces quite a bit of heat, but the moisture that it also creates is the "vessel" that this heat is traveling around in. If you use a dehumidifier, you'll actually be taking that heat back out of circulation. Surely you'll reap some benefit from the heater....I'm just thinking that the dehumidifier will just make it less efficient. If not, the companies that make these heaters would just add a dehumidifier as an integral part of the system.
Dehumidifier = Air Conditioner So that doesn't seem to be cost efficient. I would guess the reason your stucco inside and out house feels cold is due to the radiant properties of stucco as compared to Gypboard or wood siding. Like why the batroom tile feels colder than the wooden hall floor. Denser materials absorb and radiate energy more efficiently that materials with more voids and dead air space. The heat in your body is radiated faster to the more dense stucco and in turn radiated to the outside enviroment faster. It can be very expensive to try and retrofit insulation into your walls, usually requiring some demolition and reconstruction. Attic insulation however is usually easy to install and since heat tends to rise can be very efficient in reducing heating costs. The easiest solution is just wearing more clothes. Obviously this cheaply adds insulation where it does the most good. The area's where clothing is 'optiona'l are usually small and used for short periods of time. Adding an intermittant supplemental heating can be done cheaply with electric baseboard units, infared lighting units or open flame gas units. This compliments of Texas A&M School of Enviromental Design, Class of 80.
