I am close to a final design on a home to be built starting in DEC. I am looking for recommendations for engineering companies that forum members can suggest to do a manual J. My architect is farming this out and I plan to run the calculations myself but I want someone independent that can do this. Also I a curious about cost of this service you paid. I will provide all the information required to that company. My goal is to get an honest assessment of what this new home will require for HVAC. Thanks

We perform ACCA Manual 'J' heat loads.

Badger
Thanks will be in touch. I also PM'ed Doc for his recommendations too.
Will go PM as to now clutter the posts up regarding details.

You can go with a one time license on HVAC calc. Use real data (don't pad the numbers) and you will get a servicable result. The real question is what you do with the numbers once you have them. If you are going with gas fired anything it's hard to tank your results. If you go with heat pump anything there are many unevolved designers out there doing things like they did in the Carter years.

We are an engineering company, but we don’t do ACCA Manual J. We only do ASHRAE Radiant Time Series (RTS) analysis these days and only for projects that really interest us. RTS predictions much more accurately match completed project measured reality which becomes increasing important when designing large commercial buildings or high performance homes where proper HVAC sizing and operational efficiency is important.

The 1960s Manual J methodology (which was originally developed by ASHRAE back then) tends to significantly over-estimate heat loss which is generally considered acceptable by the HVAC industry for their customer market as it is conservative. We also have simple Manual J-like heat loss and cooling load software on our website for free DIYer use too.

All methods require proper determination and software entry of the required critical heat transfer building construction parameters in order to provide reasonable predictions. We have seen some very fancy Manual J software outputs with some very badly done inputs and associated poor predictions over the years.

Thanks for the information. I had read antidotal information that Manual J over estimates the load calculations by up to 30%. I have no domain knowledge in this area and having been exposed to two situations where my systems were oversized (combined with the added costs) is why I am anal about more than one Manual J that is in agreement with another.

I do plan to do an estimate myself using some of the programs available but I have no confidence in my work since this will be a first attempt but will give me better insight as to what I should see.
Not familiar with RTS but sounds like an excellent diagnostic tool for heat/ cooling calculations.

I do plan to implement geothermal for the heating and cooling but need to compare costs given I have natural gas available to me.
Appreciate the inputs...

If you have Nat Gas available then your design must be first rate or you could get the double whammy of higher first cost and higher operating cost. I'm working with a geo exchange blogger now who's designer was so poorly educated that he would have been better off with gas furnaces. Since the equipment is paid for and they used splits we may eventually change out air handlers for gas furnaces to optimize operating cost, but his (forgive the term) ROI exceeds the original equipment life.

Good point. Believe it or not the county my architect lives in does the Manual J. I have no idea of what this person's qualifications are in that county but my architect has been designing ICF, Hebel, conventional stick homes for a long time (46 years) and is well respected. I know full well spending the extra money for geo is a forward investment against rising fuel costs for generating electricity and also for rising natural gas (it will rise but not all that fast given fracking has generated a lot of supply).
Much cheaper to go with natural gas furnace (heating isn't all that needed in Florida) and high SEER AC (AC is needed 8-9 months of the year) but I have the opportunity to do this right with the build thus my concern on over estimation of heat and cooling load calculations.

I am a PE EE but not in this state and not in mechanical. I assume I can use one of the manual J programs available to get me in the ball park with what a professional service will do.

Appreciate the domain knowledge from those that do this as a livelihood as there are times experience trumps everything else...

Being a PE, even in a different discipline, will allow you to quickly learn and quickly apply what you learn to solve a problem and to also weed BS from substance. I am an EE myself and my husband is the ME. Yes, experience should normally be a positive attribute, but only if the experience is initially based on sound knowledge and one continually learns to do things right and better. Unfortunately, there is no shortage of incompetent HVAC and building contractors in this country who have lots of experience doing things poorly and never learn to do better.

Once you have a Man J calc, you can employ the geo design calculator on the Cimatemaster web site (at no charge) to model different systems. You can then compare high end air source equipment to ground source. As I understand it open loop is quite common in FL so the cost difference may not be as big as you think. Make sure the comparison is honest in that you don't cost up a code minimum duct builder against a properly designed/installed heat pump duct system. That's a common mistake to look at the least expensive conventional system and calculate the additional geo cost from there vs comparing a high end conventional system to what is one of the highest end comfort systems.

At the end of the day I expect you'll recognize what you need to. Maybe geo will be a good fit, maybe more money spent on solar makes more sense. Curt Kinder has done some remote consulting and would likely be a good one to help you seperate the wheat from the chaff here.

I appreciate the informed input. The lot sits 8 ft above a brackish bay. Open loop system would be excellent but I don't think this site location will permit that. I will need to check on that. I had abandoned open loop thinking because of the pump and dump. I could pump but concerns about the water filtering are of great concern. Dumping would be no issue assuming the water is just heated or cooled a few degrees. I am thinking of asking engineer how in his area which is the same latitude as mine how they can do so many open loop systems when in this area I have only ever seen closed loops systems. Has to be a reason I am not aware of.

I was not aware of Climatemaster design calculator. I will look into that. I did some preliminary calculations making estimates for what I am thinking for the windows, walls and ceiling. I am just working to get a feel for what would seem reasonable.

Appreciate the suggestion about Curt Kinder as well.

Also I do agree with sailawayrb that experience with no learning is not of great value. I hope to be able to find the experienced craftsman that knows what they are doing and more importantly why they are doing things the way they do. I am fortunate to have two friends in the area that have used the same geo contractor with good results.

However I need to do the trades and see if geo is my best bet (I am guessing it is) compared to ASHP. Where I live I really don't want HVAC sitting outside because it is not unusual to have strong winds from hurricanes blow salt water on to everything within 400-500 yards of the beach or bay and I sit less than 50 ft from such a source. Thus the reason I have been more interested in the GSHP sitting in a mechanical room.

The time I have spent on this forum has paid great dividends in increasing my domain knowledge. I am one meeting away from beginning the engineering work for the structure, mechanicals, etc needed for construction to start in December sometime...

"We" are not an engineering company, but we do use Manual 'J' (the US standard for residential construction of all types). "WE" are aware of the ASHRAE RTS, (a spread sheet intended for education rather than practical application). The RTS is also geared toward cooling in general and commercial buildings in particular, neither of which is pertinent in this case nor, generally speaking, in this forum. As for the 1960 version of Manual "J"; the inception of a methodology is only historically relevant it nexus.

http://www.acca.org/technical-manual/manual-j/

The only exception to this statement is the proper modelling of radiant floors, walls and ceilings that tend to raise the mean radiant temperature of a structure while lowering the ambient air temperature, typical yielding 10% lower heat loads. The best way to account for these lower loads is to use one of the many radiant-specific heat load calculation software programs developed by industry leaders e.g. LoopCAD, and "our" favorite, Wrightsoft whom worked with Uponor (the industry leader) to develop a module specific to radiant panel heating. There is nothing more accurate or precise when trusted to an experienced designer.

"We also are arrogant beyond words, and only dust off the old CRT when profoundly moved by a project exhibiting a compelling, ethereal magnetism, too strong to ignore. It helps if we share common goals for our environment, our community and our hair color...

Actually, RTS is intended for heating loss analysis and CLTD is intended to cooling load analysis. In fact, these days you can even get ASHRAE CLTD/RTS from Wrightsoft:

Wrightsoft CLTD/RTS Software

Of course, it is somewhat pricy and like all their software, it must put ease of use well above accuracy/capability in order to address/mitigate typical low level HVAC contractor competence. Nevertheless, it does have a fancy output that will impress most customers and this should likely make it a big hit with the HVAC industry.