Wait to replace water heater?

[colinml]

I was about to purchase a new propane water heater (standard tank type) to replace the old, inefficient one that came with the house we purchased last year when I stumbled across something about heat pumps being used to heat water, in addition being used in HVAC. I happen to have an equally old and inefficient propane furnace right next to the water heater. I was thinking "first I'll do the water and then deal with the furnace," but now I wonder if I might be missing an opportunity by going ahead with the water heater before investigating the furnace (and possible heat pump). I know nothing about heat pumps, so there is a great deal of research I need to do, but, in the meantime, is this a definite "Oh yeah, you should absolutely wait on the water heater until you look into the heat pump" thing?

I'm in Bellingham, WA (2 hours north of Seattle). Climate is mild. We get a few weeks in winter when the temps can dip into the 20s at night. I don't really need air conditioning in summer. My main interest is that 500 gallon propane tank in my yard, which is awfully expensive to fill, and my furnace sucks it dry quite quickly.

[motoguy128]

You're probably a godo candidate for a dual fuel system for you heating. Using both a heat pump and propane furnace.

For water heating. The heat pump based units are independant of the HVAC system. They are for people that are all electric and have higher electric rates.

There are "economizers" that use a coil connected inline with the refrigerant loop that preheat the water when you use the AC. But since you are in a colder climate it won't work well... and IMO are not worth the cost.

You should probably look at a tankless hot water heater and still use propane. I suppsoe you could consider a solar hot water preheater. But I'm not a big fan of that stuff either. ROI isn't very good... and probably won't last much past the payback period before it needs replacement.

[tipsrfine]

Don't buy any furnace until you have your home evaluated for how effective it is at keeping the heat in. The reason your furnace sucks the propane tank dry quickly is because your furnace has to keep replacing the heat that is escaping it. Have someone trained in Building Science that is BPI or RESNET trained to perform an energy audit on your home. Putting some money into properly air sealing your home & adding insulation where needed, along with air sealing your duct system will not only reduce the amount of propane you are using, but will allow you to install a smaller furnace, and will increase your overall comfort in the home.

[colinml]

Thanks for the replies. I thought there might be some combined water and HVAC heat pump thing, and I didn't want to miss the chance to look at that. Sounds like I can proceed as I have been.

My plan is to deal with water heating issues immediately, while at the same time going around and correcting all the heat that is escaping. Then, after I feel I've done the best I can with sealing the envelope, I will call in the HVAC experts to show me what I missed. I'm comfortable with that approach because there is so much to do that is patently obvious, sans need for thermal imaging. There are also some basic passive things that were designed in to the house when it was built, but were never completed, or need some attention. I just glazed in the attached greenhouse, for instance, and now I can open the doors when it's 30 degrees out and get warm air. There's also unlimited free firewood from the surrounding property, but we've only replaced one of the woodstoves so far. The other one is from the seventies and not worth using.

So, basically, I will probably spend this winter correcting the obvious and start talking to HVAC people next summer. That gives me time to research. I suppose I will be around here quite a bit.

Thanks again.

[tipsrfine]

Google "energy star thermal bypass checklist" and you should find that list that will be a great aid in your air sealing & insulation endeavers.

[colinml]

That does look helpful. Thanks again.