About to retire, so thought I'd give myself a bon voyage gift to lift my creature comfort/spirits aboard ship by installing a central air/heat unit. Any/all ideas and reccomendations (and cost) would be appreciated
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A Heat Pump Fact
They are more efficient in the heating mode than in the cooling mode. In your area that will be a plus.
They are more efficient in the heating mode than in the cooling mode. In your area that will be a plus.
Heating/Cooling
Good for you about to retire. I am working on that. I have been researching such topic and found Home Depot sells a portable AC-heating unit (120V 6000BTU) in the spring time. It has a 5-6 inch dia flexible hose to exhaust hot air out thru a window. The unit has wheels so you can move it around. It's air cooled so no need to drill holes on the boat. Worth take a look at.
Good for you about to retire. I am working on that. I have been researching such topic and found Home Depot sells a portable AC-heating unit (120V 6000BTU) in the spring time. It has a 5-6 inch dia flexible hose to exhaust hot air out thru a window. The unit has wheels so you can move it around. It's air cooled so no need to drill holes on the boat. Worth take a look at.
Portable AC unit
I tried one and it worked great in my bedroom, but on the boat (28.5') it took up too much space and the heat generated through the exhaust hose pretty much offset the cooling. It would probably work better on a larger boat where the unit could be located farther from the living space.
I tried one and it worked great in my bedroom, but on the boat (28.5') it took up too much space and the heat generated through the exhaust hose pretty much offset the cooling. It would probably work better on a larger boat where the unit could be located farther from the living space.
Reverse Cycle
If you want a good, no hassle reverse cycle unit, get one that is for a boat. Most of the suggestions above, are not for marine use. I have a Catalina 320 with a 16,500 Mermaid unit that works great...just like central air at home, cycles on and off and has a digial thermostat.
If you want a good, no hassle reverse cycle unit, get one that is for a boat. Most of the suggestions above, are not for marine use. I have a Catalina 320 with a 16,500 Mermaid unit that works great...just like central air at home, cycles on and off and has a digial thermostat.
mermaid 16500
I'll also vote for the mermaid-both heat and cool work really well on our 356, and it was easy to install. Defender had the best price, watch for winter sales
I'll also vote for the mermaid-both heat and cool work really well on our 356, and it was easy to install. Defender had the best price, watch for winter sales
More Efficient in COOLING Mode
Reverse-Cycle Heat pump efficiency is determined by comparing the amount of energy delivered by the heat pump to the amount of energy it consumes - the higher the number the higher the efficiency of the system. In North America, “Energy Star” Heat Pumps must have a minimum HSPF* of 7 (5-6 is ‘standard’), and SEER of 12* (8-10 is ‘standard’). Hence, it can be said that Heat Pumps are much more efficient in Cooling mode. HSPF = Heating Season Performance Factor (Heating Performance) - the estimated seasonal heating output in BTUs divided by the seasonal power consumption in watts. SEER = Seasonal Energy Efficiency Ratio (Cooling Performance) - the total cooling of the heat pump in BTUs divided by the total electrical energy input in watt-hours during the same period.
Reverse-Cycle Heat pump efficiency is determined by comparing the amount of energy delivered by the heat pump to the amount of energy it consumes - the higher the number the higher the efficiency of the system. In North America, “Energy Star” Heat Pumps must have a minimum HSPF* of 7 (5-6 is ‘standard’), and SEER of 12* (8-10 is ‘standard’). Hence, it can be said that Heat Pumps are much more efficient in Cooling mode. HSPF = Heating Season Performance Factor (Heating Performance) - the estimated seasonal heating output in BTUs divided by the seasonal power consumption in watts. SEER = Seasonal Energy Efficiency Ratio (Cooling Performance) - the total cooling of the heat pump in BTUs divided by the total electrical energy input in watt-hours during the same period.
Since you're in California...
Jim, being out west Mermaid Marine may not be a familiar name to you. This biz is located in Ft. Myers, FL and was started up by seveal former cruisers, who generated a solid rep for good value and customer service, then sold out to a new owner who's run the biz the last 5 years or so. Our MM unit is now almost 10 years old, we've used it 'hard' (in Florida) for a few years of that time, more recently in London (for heat) and Spain (for cooling). After returning from the Caribbean in 2002, we went back to the 'factory' (its more of an assembly facility + offices, since they buy not manufacture the components), met the staff, and had our unit upgraded. This visit told us that the new owners were very responsive to 'old' customer needs, had upgraded the units substantially since we'd bought ours, could support old products, and hire nice but also sharp techs. We continue to be impressed with MM and, were I in CA with a boat, I'd be reassured that they can provide decent customer support altho' at some distance away. OTOH dealing with a local vendor may provide you with nearby support you feel you need; that would be your call. Were I you & shopping for an HVAC system, I'd call MM and have a chat; I think they're worth considering. Installing one of these systems is very easy in a technical sense; the challenges are mostly drilling big holes thru thick bulkheads.<g> Jack
Jim, being out west Mermaid Marine may not be a familiar name to you. This biz is located in Ft. Myers, FL and was started up by seveal former cruisers, who generated a solid rep for good value and customer service, then sold out to a new owner who's run the biz the last 5 years or so. Our MM unit is now almost 10 years old, we've used it 'hard' (in Florida) for a few years of that time, more recently in London (for heat) and Spain (for cooling). After returning from the Caribbean in 2002, we went back to the 'factory' (its more of an assembly facility + offices, since they buy not manufacture the components), met the staff, and had our unit upgraded. This visit told us that the new owners were very responsive to 'old' customer needs, had upgraded the units substantially since we'd bought ours, could support old products, and hire nice but also sharp techs. We continue to be impressed with MM and, were I in CA with a boat, I'd be reassured that they can provide decent customer support altho' at some distance away. OTOH dealing with a local vendor may provide you with nearby support you feel you need; that would be your call. Were I you & shopping for an HVAC system, I'd call MM and have a chat; I think they're worth considering. Installing one of these systems is very easy in a technical sense; the challenges are mostly drilling big holes thru thick bulkheads.<g> Jack
Don't be confused with
SEER ratings and HSPF ratings. I doubt that any "marine" units are even rated. The reverse cycle units(heat pumps)are just as efficient as a simular model straight a/c for cooling. The difference comes in heating. A straight cool unit will have resistence heat strips (think hair dryer) for heating. Heat strips are 100% effecient at heating, however they consume alot of power. A heat pump uses less power to produce the same (depending on water temp)heat making it more than 100% effecient(that's it's COP, Coeffecient of Performance). So a heat pump does produce more heat for the power used, as compared to cooling. But comparing the HSPF and SEER of the same unit is not the comparison to use.(They are arrived at using different tests and standards.)Therefore they mean different things. SO as compared to ITSELF ONLY a heat pump IS more effecient in Heating than Cooling. (My Apoligies to Jim Rushing). But not less effecient at cooling as compared to an straight a/c unit. So if you pay for electricity, and your home waters are above 35-40 degrees a reverse cycle unit is a good choice. I also second the Mermaid unit for cost and quality. The main installation issues I have on mine are; keep the water pump as low as possible for priming, besure and have the correct size and number of ducts, including the return air. With too small or not enough airflow you'll have problems with high pressure cutout in winter and icing in summer. Also noise can be an issue if the unit is touching the hull or sides of a locker. And remember when you're cutting 4 & 5" holes thru bulkheads, a good fiberglass guy can repair mistakes as good as new. Good luck, and do get a marine unit that's permanently installed. dwain
SEER ratings and HSPF ratings. I doubt that any "marine" units are even rated. The reverse cycle units(heat pumps)are just as efficient as a simular model straight a/c for cooling. The difference comes in heating. A straight cool unit will have resistence heat strips (think hair dryer) for heating. Heat strips are 100% effecient at heating, however they consume alot of power. A heat pump uses less power to produce the same (depending on water temp)heat making it more than 100% effecient(that's it's COP, Coeffecient of Performance). So a heat pump does produce more heat for the power used, as compared to cooling. But comparing the HSPF and SEER of the same unit is not the comparison to use.(They are arrived at using different tests and standards.)Therefore they mean different things. SO as compared to ITSELF ONLY a heat pump IS more effecient in Heating than Cooling. (My Apoligies to Jim Rushing). But not less effecient at cooling as compared to an straight a/c unit. So if you pay for electricity, and your home waters are above 35-40 degrees a reverse cycle unit is a good choice. I also second the Mermaid unit for cost and quality. The main installation issues I have on mine are; keep the water pump as low as possible for priming, besure and have the correct size and number of ducts, including the return air. With too small or not enough airflow you'll have problems with high pressure cutout in winter and icing in summer. Also noise can be an issue if the unit is touching the hull or sides of a locker. And remember when you're cutting 4 & 5" holes thru bulkheads, a good fiberglass guy can repair mistakes as good as new. Good luck, and do get a marine unit that's permanently installed. dwain
All I know is that
I can heat the boat to 72 degrees when it is below freezing outside, but I can't cool the boat more than 15 less than the outside temperture. So when it is 100 degrees outside, it is at best 85 inside. And it has been over 100 degrees a lot this year. Matter of fact just last week. Where's winter when you need it.
I can heat the boat to 72 degrees when it is below freezing outside, but I can't cool the boat more than 15 less than the outside temperture. So when it is 100 degrees outside, it is at best 85 inside. And it has been over 100 degrees a lot this year. Matter of fact just last week. Where's winter when you need it.
Other factors
There are other factors to consider. Take for example in house. I have in the past turn the heater off and had to open windows during christmas because of the heat generated by the people in the house, the cooking in the house, and the heat generated from all the sun that comes through the windows (my house is built a lot like a Earthship type home) and that when it was about 50 degrees outside. I remember when I was in Baltimore. I never had to turn the heater on. Between the heat from the refrig, the stove pilots, and the heat rising from the floor below, it stayed about 70 degrees when it was 20 outside. I realized the heat from the refrig and stove during the summer...man it was a hot apartment. So, in a small boat, the heat from the cooking, the human bodies and the heat from running the heater (not the output) and refrig will all add up a bit.
There are other factors to consider. Take for example in house. I have in the past turn the heater off and had to open windows during christmas because of the heat generated by the people in the house, the cooking in the house, and the heat generated from all the sun that comes through the windows (my house is built a lot like a Earthship type home) and that when it was about 50 degrees outside. I remember when I was in Baltimore. I never had to turn the heater on. Between the heat from the refrig, the stove pilots, and the heat rising from the floor below, it stayed about 70 degrees when it was 20 outside. I realized the heat from the refrig and stove during the summer...man it was a hot apartment. So, in a small boat, the heat from the cooking, the human bodies and the heat from running the heater (not the output) and refrig will all add up a bit.
And other factors
I too have the same results as Jim R and I've always wondered how much the intake water temp influences the cooling and heating efficiency. On Lake Travis the water temp is 85 to 90 degrees on 100 degrees days and it takes 2 1/2 to 3 hours to knock the cabin temp down to 85. In the winter the water temp is 60 to 65 degrees and the reverse cycle function produces plenty of heat when the outside air temp gets down to 35 40 degrees. I can get the cabin temp up to 70 degrees in an hour. So, does anybody know the math to calculate cooling and heating outputs with respect to the intake water temperatures? Several years ago, before we installed the Mermaid system I bought one of those 6000 BTU portable units on wheels and it was totally useless for temperatures over 80 degrees. I contacted the service department and they told me that these units would only cool the output air a maximum of 15 degrees less than the intake air temp if that was less than 90 degrees. I have have never measured the Mermaid output temp but I can tell you that it is much, much colder than that poor excuse for an air conditioner was. Jim what ever system you decide on consider buying the Mermaid Air condensator. The condensator removes the condensate water from the pan by a venturi process out to the AC water cooling drain. It's a little pricey but you will have a dry bilge.
I too have the same results as Jim R and I've always wondered how much the intake water temp influences the cooling and heating efficiency. On Lake Travis the water temp is 85 to 90 degrees on 100 degrees days and it takes 2 1/2 to 3 hours to knock the cabin temp down to 85. In the winter the water temp is 60 to 65 degrees and the reverse cycle function produces plenty of heat when the outside air temp gets down to 35 40 degrees. I can get the cabin temp up to 70 degrees in an hour. So, does anybody know the math to calculate cooling and heating outputs with respect to the intake water temperatures? Several years ago, before we installed the Mermaid system I bought one of those 6000 BTU portable units on wheels and it was totally useless for temperatures over 80 degrees. I contacted the service department and they told me that these units would only cool the output air a maximum of 15 degrees less than the intake air temp if that was less than 90 degrees. I have have never measured the Mermaid output temp but I can tell you that it is much, much colder than that poor excuse for an air conditioner was. Jim what ever system you decide on consider buying the Mermaid Air condensator. The condensator removes the condensate water from the pan by a venturi process out to the AC water cooling drain. It's a little pricey but you will have a dry bilge.
You might check
with Mermaid too see if they have a "ARI" performance chart for your system. It will tell you capacities at different temps. They also should be able to tell you if your unit is sized correctly for your conditions. You are correct in thinking that just as you need more cooling the higher water temps are reducing your unit's capacity. Humidity, amount of water flow, and amount of air flow will all affect a unit's performance. By the way, you don't want too cool of air output. A delta T of about 20 degrees + or - is good. If it's higher you can benefit from more air flow. A higher volume of cool air will cool the space better than a lower volume of colder air. (Did that make any sense?
) Plus if will dehumidify better, which will then allow the unit to cool better. If you size a unit for cooling in a warm climate it will be extremely oversized for heating, making heating a nonissue. dwain
with Mermaid too see if they have a "ARI" performance chart for your system. It will tell you capacities at different temps. They also should be able to tell you if your unit is sized correctly for your conditions. You are correct in thinking that just as you need more cooling the higher water temps are reducing your unit's capacity. Humidity, amount of water flow, and amount of air flow will all affect a unit's performance. By the way, you don't want too cool of air output. A delta T of about 20 degrees + or - is good. If it's higher you can benefit from more air flow. A higher volume of cool air will cool the space better than a lower volume of colder air. (Did that make any sense?
) Plus if will dehumidify better, which will then allow the unit to cool better. If you size a unit for cooling in a warm climate it will be extremely oversized for heating, making heating a nonissue. dwainInformation
Jim...you are getting way too much information here. Do what you said you were going to do in your original post. Check out a good marine reverse cycle unit and either put it in or have it put in, you'll love it. This is a Ford/Chevy, Catalina/Hunter question.
Jim...you are getting way too much information here. Do what you said you were going to do in your original post. Check out a good marine reverse cycle unit and either put it in or have it put in, you'll love it. This is a Ford/Chevy, Catalina/Hunter question.
Thanks to all
for their input/advice. Very much appreciated. I will soon begin investigating reverse cycle products/costs/ and installation and will most certainly check out the Memmaid units.
for their input/advice. Very much appreciated. I will soon begin investigating reverse cycle products/costs/ and installation and will most certainly check out the Memmaid units.
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