This may be old news, but I hate to assume. I’ve been searching for a cost-effective, yet accurate, temperature and humidity sensor. I recently learned of the Si-7021, but being surface mounted, it caused me concern due to my lack of experience with that type of soldering. Well…Silicon Labs also offers their Si-7013, which is similar in specs but happens to match up with Schmartboard’s 204-0022-001 offering that makes soldering and interconnecting a simple (supposedly) matter. Yes, the addition of the Schmartboard effectively doubles the total cost to about $11 (via Mouser), but it’s now within my skill and tool capability.
thanks for the news. This is something I am interested in.
Surface mount soldering can be really easy and I would encourage you to give it a try. 1. professional pcb with soldermask (oshpark)
2. solder paste - I use no-clean paste Chip Quik that I bought from digikey. I have used paste and stencil or else paste from a syringe. You can just put a blob of paste over these tracks and the solder will automagically flow to the correct spot.
- I use a controlled toaster oven but some people control the toaster manually and get things to work just fine. You can also use a hot air station but my feeling is that skill and practice would be required to do it properly. With a controller on the oven, I just hit go and let the controller do the job.
I just can’t get over how foolproof this process seems to be.
I am working on a breakout board for the imp 001, and it mostly use smd components. First time I did smd I was very unsure if I actually could do it, but if you design a pcb (I design mine in eagle), and then get that pcb made cheap in china, you get the soldermask and all which will make it easy for you.
To solder my boards I use solder paste, and even if you use a bit too much (not way too much), it will still reflow just fine because of the solder mask and the surface tension of the solder.
First time you reflow you don’t even have to get any special equipment to give it a shot. The way I did it was to get a little pcb made, then just put the solder paste on, placed the components, put the pcb directly on my stove and turned it on full. I then kept an eye on it to see when it started to reflow, and then removed it from the heat plate. Job done, and it worked. 
Using the stove and no temperature control won’t work for all components, as some are more sensitive to temperature than others, but my first pcb was just a few capacitors, resistors and leds. But if you start out with something simple just to see if you can do smd soldering, it does not cost much to give it a shot. So far I am down to soldering 0805 components.