Add Improved Baseboard - after oil to gas conversion contractor suggests more spend - huge miss ?

You'll have to remove those prices. But the answer is no, oil vs. gas doesn't change the output of baseboard. Higher temperatures will output more and gas can hit those higher temperatures (the limiting factor is the water, not the fuel). For free, you can increase the water temperature, automatically, for the coldest outdoor temperatures with little change in efficiency since these temperatures are rare.

Find a new guy.

Not supposed to talk pricing on here, might want to edit that out.

My recommendation is to hire someone else. There was either a miscommunication between the two of you at install time or the guy messed up. If you are saying now that the area struggled to heat in the past that should have been discussed prior to install. Sometimes on retrofit, installers will assume the space was heating well unless told differently by the people living in the space. Sometimes homeowners will hire a company to change a piece of equipment and leave out important details to try to make the new installer own past mistakes. A conversation about your heating system is a pretty important step in the install process in my opinion to avoid either of these situations occurring.

That all being said making assumptions that things are working well is not the best way to operate, especially considering that they are aware the output of the emitters has changed now that the entering water temperature has changed. for that reason I would hire a different company and cut ties on good terms with the other ones. Of course if you have something that shows you had hired them to provide MORE heat to the space that was struggling, you may have a leg to stand on getting the work done at no charge but it sounds unlikely as neither party seems to have been properly informed about the scope of work needing to be done.

That's not enough to troubleshoot - it could be inadequate flow, inaccurate aquastat, etc. It seems unlikely that you're 5 degrees under setpoint now but weren't before solely because the baseboard is short, so adding radiation should be the last resort for you (but most profitable for them). Another option would be to ensure nothing has changed with the building envelope downstairs - perhaps the output is the same as before but now the heat loss is higher. Improving insulation/air sealing might be a cheaper route too.

You have to start with a heat loss calculation for the building and work from there. There are online calculators and applications where you can do this yourself.

You will get a heat loss for each room and you can compare that to the amount of heat the emitter in each room can supply at various water temps.

Unless there is a lot less emitter on the first floor compared to the second or there is a whole lot of glass or something else unusual about the architecture of the first floor your issue likely lies elsewhere since the roof will have a lot more heat loss than just walls on the first floor. Also possible all the heat from the first floor rises to the second.

It could even be a piping issue or a hidden balancing valve or strainer somewhere or a misapplied zone valve or any number of other design or service issues with the system causing the 1st floor to not get enough flow.

I had just acquired a new fuel dealer to do service calls for their customers, some years ago (after his top technician retired). One of my first service calls for the new company was on an unusually cold winter night. They had just installed a new Columbia boiler the previous winter. I looked at the great plumbing job, the site built manifold and the zone valves were very pretty. The only problem was that all the near boiler piping was 3/4". Supply manifold from the boiler to 3 zone valves were all 3/4". Same on the return, All 3/4" teed to 3/4" manifold back to the boiler return. I explained that this would not work because the supply manifold needed to be at least 1" to each zone valve with a 3/4" branch to each zone valve. The customer then told me that the Fuel Dealer just installed the boiler last year. So I told the manager of the fuel oil company what the problem was and gave him a reasonable price to make the correction. This manager wanted to hear nothing about it. "We installed it last year and it worked fine". There was no telling him how to fix it or that they should eat the cost of doing it correctly.

I offer this story for 2 reasons. First I should have asked who installed the boiler before I told the customer what the problem was.
SEE https://forum.heatinghelp.com/discussion/188729/dead-men-tales-the-dopey-kid-who-used-to-wear-your-clothes#latest
...and second: You have something that has changed between the previous boiler and this new boiler, (like that customer) and it has nothing to do with the fuel. It most likely has to do with the water temperature being set lower than the old boiler water temperature OR perhaps an overlooked piping design at the near boiler piping. As suggested by @Hot_water_fan, @Jamie Hall and others have suggested.

Either way, we could use some pictures of your near boiler piping from at least 3 different angles from far enough back to see the floor to ceiling piping. The different angles will help the determine where closer pipes cover up other pipes behind them.

There may be an easy fix or there may be another answer.

Finally, Make sure the baseboard radiators are clean, The under side of the aluminum fins can collect a lot of dust that will block air flow thru the convector. Also see that any dampers that are closed are fully opened. The dampers are there to reduce the output of the radiator if you want to have a cooler room. and finally, be sure that the under side of the radiator cover is at least 1" above the floor covering. Sometimes wall to wall carpet is installed in a way that reduces the air flow at the bottom of the baseboard radiator (Ask me how I know).
I hope these tips will help.

Mr.Ed

@retiredguy

How many schools did you go into where the Unit Ventilators were covered on top with books and papers so they couldn't heat?

Just to add to this post as a remember to do when looking at any hot water boiler for either a service call or bidding to replace a hot water boiler is to check the aquastat settings . It seems that durning the mid to late 70 s w the rising prices of fuel and material that a lot of contractors where doing at little corner cutting in a lot of cases it was raising the aquastats up to 190-200 and cutting down on baseboard or even better install 1/2 piping and baseboard and run it at 230 .
On both of these set up they worked ok w any set back but as soon as set backs where used and below average temps where upon them I see when the issues would start . Another issue that occurs w 200 degree and over is baseboard ghosting issue depending on wall insulation which will stain the wall over and over again until the aquastat is lowered ,been there done that this is why I know .
So when I look at either service or replacement jobs ,pull that cover off and check it out never know what you many find and with out looking u may be in trouble down the road and lose any trust your customer may have had it you .
Not to sound like a preacher but when installing a modulating condensing boiler one of the contractors first thought should be will this unit operate in condensing mode ,will this unit at design day and set at it’s maximum temp heat this home as it did previously .if the answer to any of these question is no then stick to a hi temp cast iron boiler and do the chimney liner and Be done and be happy no issues . Again mod con ain’t for every job in my option there only as good a side the system you connect to and if it cannot heat the home w lower temps it a wash and go w a standard cast iron boiler . Peace and good luck clammy